Digging Claws: Like this isn't painfully obvious! Grinder has larger, long, and durable digging claws, sharp enough to cleave through any stone, though natural metals will slow him down, he'll still get through eventually. These claws are also a deadly weapon, though not as much as the crystals that can be used to augment them. Naturally, given that they've been used for who knows how many millennia to break, cleave, shove, and pulverize countless thousands of tons of stone to dig through the ground as if swimming, these arms are also incredibly strong.

Tremor Sense: Special sensory organs hidden in his nose, as well as those strange whiskers, and nerves throughout his body enable him to sense incredibly minute vibrations to learn about his environment. though this primarily refers to vibrations in the ground, it can be applied to some degree to anything that displaces enough air or 'mass' in general to create a signal. Basically, air-borne and under-water targets are not invisible to him, though the returned signals a bit more unclear, and he will more often combine this with his actual eye-sight to track such threats.

Hyper-Sensory Reaction: Probably not many people know, but moles are some of the fastest reacting animals in nature, capable of registering something as edible in nearly a hundredth of a second, and snapping on it in a tenth... Granted, this incredible speed doesn't 'precisely' translate to a titanic lumbering beast's actual body, but he is still capable of processing and reacting to an incredible volume of stimuli with astoundingly rapid timing... he just has to compensate for his body's far slower movement compared to his brain, but suffice to say, you don't want those jaws close enough to bite you.

Crystal Growths: The precise durability of these crystal growths is unclear, but they've proven able to with-stand incredible heat and force, and are obviously meant to be capable of withstanding the force and pressure of the earth while digging through it rapidly and facing normally deadly hazards such as magma pockets, cave-ins, explosive gas chambers, untold 'megatons' of earth naturally moving around it while being dug through. They've also demonstrated refractive properties, and a strange frequency that their matter seems to vibrate at, assumedly helping with digging as well as locating the crystals when dislodged. Oddly enough, they've also demonstrated solar absorbing properties when in the sun-light, though visible effect has been minimal, it's theorized that their growth may be solar powered to some degree.

Mineral Shaping: This strange ability allows him influence on the crystals that litter his body, allowing him to quickly grow, regrow, or re-shape them while they are directly attached to him and easily manipulated, contact manipulation is possible but noticeably slower. This includes re-shaping them in motion so that they can be flung off of his body, though once a crystal leaves his body It's beyond his reach.

[After some talk with the GM, I figured I should explain this one a bit thoroughly in my final product]
Refractory Crystal Beam: The beam itself is comprised of solar energy drawn in through the crystals on his body, and collected within, though what precisely takes place 'inside' is unknown, it is clearly stored in sizeable volumes and can be projected from his mouth as raw light energy, varying between a bright harmless flash of light with short range to a focused beam of magnified light with a greater range and a focused heat limit capable of melting through steel beams like butter until it loses some of it's power, as well as being refracted by the crystals ejected from his body.

[It was suggested I go a bit farther with the explanation here! So lets see if I can make my idea clear!]
Basically, crystals inside his body act like Solar batteries, gathering solar power that reaches the crystals on the outside of his body, storing it enough volume to create a focused beam akin to a magnifying glass beam, but scaled up to a kaiju's size.

The fundamental function of it is like a self-charging heat-laser who's power drops as the charge lowers, and while it has charge it can vary it's out-put, such as low enough to match it's recharge rate, where it would either have pitiful range, effect, 'or' spread, but be able to be re-used easily without much drain. While it can be used at maximum power, giving it good range and enough effect to melt through sky-scrapers like butter, essentially like a plasma cutter to put it simply, but only able to be powered for a few seconds before his charge is too drained to maintain that level of damage.

General Resistances: Blunt force is almost always easily shrugged off, given the forces of the 'planet' he has to survive while digging, this isn't much of a surprise. Though not immune, he 'is' highly resistant to cold with that thick fur, and generally fire-proof given, once more, what he often digs through under-ground. He's somewhat resistant to electricity, but Solar energy in particular is easily absorbed as more power.

General vulnerabilities: While cold has little 'influence' on him, he's still capable of being physically frozen, and in a similar sense, despite being fire-proof he can be enflamed to some degree, and the fire has other issues of it's own, such as heat distorting the air that he senses vibrations in above ground... Many 'general' weaknesses can be attributed to basic physics and the natural effects things have on the world around them. The crystals on his body may be capable of refracting energy, but the rest of his body is not so strong against it.

Sensory Vulnerability: Quite simply, as sensitive as his tremor sense is, this also comes with being easily disrupted in a variety of ways and intensities, or sometimes bypassed entirely... obviously, there's too many possible ways to do this to actually list them all, but the simplest and biggest ones I can point out would be sonic attacks, over-loading vibrations, or something that makes no or so little vibrations, or moves faster 'than' those vibrations. You need only your imagination ;3

Hyper-Sense Difficulties: While he's capable of processing and reacting in fractions of a second, his body is not capable of 'moving' with the same speed, while he's not 'slow' either, and it still presents an advantage in reaction times, the difference in thought speed and physical movement speed can clash sometimes, and lead to frequently clumsy movements, especially when things become stressful and times 'to' react grow tighter.

Circadian Rhythm Downtime: While the effects are not so strong as to render him unconscious, Certain times of day, as well as specific levels of lighting can cause him to become more sluggish, inducing a feeling of mild fatigue from his body's natural reaction, this usually relates to time-periods close to mid-day.

One Secret Crippling weakness: I know, this is probably a fishy thing to do, but it's so effective that being clear about it seems silly... I will say, It's related more to his 'abilities' than his other weaknesses, and ironically, more likely that the humans will figure out how to take advantage of it.

Core of Fire: 70 Meters tall at the shoulders, 80~ meters long

Life Force Power: Gaia is powered by the presence of living things, the ambient life force fuels his body and all associated powers with a pool of energy that regenerates depending on life in the environment, and though it's absence won't kill him, it severely weakens his regeneration. Also, though he can't 'draw' power directly from them in the sense of draining them, it is possible for it to be offered willingly to empower him.

Malleable Metal Body: His body is extremely durable, though it's always prone to it's quadrupedal shape, it can be reshaped in minor ways, such as producing spikes, armor, or sharp reinforcement for a weapon, drawing mass from the rest of the body to empower another part, or alter the density of the metal, with various results such as making himself appear larger, or smaller, more flexible, or more hardy... As a general rule, the lower the density of a limb, the more flexible it is, but the less durable, and vice-versa. This also means that he can easily replace lost body parts with mass from the rest of his body, which still means it won't be as durable as before, but become more mobile as a result.

Hot Body!: Literally, his body is extremely hot, though not fatally hot on the outside, which implies he has control of this heat and withholds it's greater volume inside of his body. This also is likely the reason that his 'inner' body is molten and his outer body is solid metal, it's likely that he can shunt this heat into a limb and potentially turn it molten as well. The heat within though is akin to the planet's core, and able to be expelled in a variety of ways aside from simply moving it around within his body, which normally implies an oral projection... It is probably also possible to simply disperse the heat and soften his body for greater flexibility, or compact the heat to increase hardness... given that the heat is always centered 'inside' of his body, it's possible there is something more important in there.

Mild Earth Manipulation: Stone, metal, and other minerals, he can 'somewhat' influence them in his current state, though his strength is clearly within his own body, he can impose 'some' of that will on stone and metal that he comes in contact with, which in addition to it's uses against an enemy, Is his primary method of regaining lost mass, absorbing various metals to replace lost metal or increase his over-all content. This however, is a slow and energy intensive process, anything above a small regeneration or quick 'patch-job' cannot be pulled off without time to focus on it.

General Resistances: Given the content of his body, certain things just don't affect him well, electricity for instance, has nothing to 'harm' and would simply travel through him, even imparting some of it's energy into heat as it traveles. Other sources of heat can of course provide more for him, though outside of a volcanic heat it's really not going to give him much. Poisons similar don't have a biological body 'to' poison.

Life Force Limitations: Gaia is fueled by life force, the less life there is in his vicinity the slower he can recharge, and the less he can put into regenerating his energy, or powering certain abilities, or eventually his own body. This by extension gives him a powerful motivation to protect large sources of life, and likely to encourage reckless behavior to preserve it.

Frigid Antithesis: Cold, water, and ice aren't so much a direct 'weakness' as they are mutually opposed to his strength. Water has the least actual effect, given that it would only chill his outside, greater sources of 'reducing temperature' though have the direct effect of, while hardening his body from loss of heat, also making him more durable, it also slows him down, steadily making it harder to move over-time, eventually able to freeze him, or perhaps, cool him enough to become 'too' solid.

Firey Over-use: Over-use of the heat in his core will, predictably, reduce his overall warmth, and by extension, forcibly cool and slow down the rest of his body, he has to either give it time to build heat back up, expend energy to boost his heat, or find another source to absorb heat from. By extension, this means that his strongest heat attacks are his first, and he must was a disproportionate period for the heat to build back up to full naturally. By extension though, it's also possible to forcibly over-heat his body until it melts, not that this is fatal, but it is wholly inconvenient!... unfortunately, this also tends to result in intense heat expulsion that is likely to melt the surrounding area to prevent it.

General Weaknesses: Death, sounds silly perhaps, but killing things around him, destroying forests, demolishing populated buildings, and other such sources of considerable death will weaken his ability to fuel his body. Otherwise, Things that tend to threaten metals still pose a considerable threat, though it's possible to 'cook' most of them off, like acid or rust for instance, he cannot magically undo damage that has been done this way. He is also far from immune to physics, for instance, something cold successfully entering his body tends to be fairly explosive with the reaction of temperatures... then there's magnets, yes, his body is magnetically active.