Here's my old Raven write-up.

The Ravens, as a scavenger group, cannot easily mass produce Kensai. Thus, almost all their Kensai are either stolen or custom made. There is a pseudo-feudal system where one proficient pilot will be supported by a cadre of scientists, mechanics, and other "vassals", in maintaining a top-notch Kensai, or as close as the research deprived Ravens can manage. As the Kensai Pilot brings in loot and other material from raids or scavenging trips, they expand their power base, potentially giving stolen Kensai to some of their more loyal and proficient vassals to make them "men-at-arms", so to speak. Extremely proficient Pilots will even give resources to Pilots who have run into hard times (perhaps because they don't have enough resources to maintain their Kensai) in order to strengthen their own position and have the other Pilots "owe them one".

While the Raven Kensai may not have particularly advanced technology, they have innovative uses of current technology due to the masses of inventors and mechanics aspiring to put any edge they can on their "lords" Kensai. There is no such thing as a “standard” Raven Kensai. Every one likely has some bizarre trick up its sleeve unless it is freshly captured. In other words, every Raven Kensai is a custom-Kensai. In other other words, every Raven Kensai is a custom-Kensai with crappy performance.

Raven Technology does have a primary weakness, armor. The metals that the Kensai have access too are generally metal that has been shot at a lot. While the Raven mechanics are highly adept at patching up said armor, they do not have the infrastructure to melt it down a full size armor plate and reforge it to original specs. Every patch job weakens the armor. Likewise, Ravens have to have mobility to run away from larger forces, so they must skimp on the amount on the armor. This, combined with the fact that every shot taken on your Kensai is something you will have to compensate for by capturing or salvaging more gear, means that Raven Kensai really, really don’t want to get hit. And so they have come up with many ways not to be hit.

Crystal Railgun(Weapon System): Many times the crystal of the main engine of any given Kensai salvaged by the Ravens is damaged. This means that the Ravens have access to a disproportionate ratio of small crystals to equip to subsystems on their Kensai. Against high-end mechs, energy based weapons are often not the way to beat them. Thus, a long range conventional weapon is necessary. Railguns fit the bill, and the Ravens have become adept at using the smaller salvaged crystals they have available to produce capacitors for extremely high performance railguns. These railguns generally fire once and then are done until recharged, but generally that’s all the Ravens want to do. Strike devastatingly with overwhelming force from beyond enemy range, then grab loot and run away before reinforcements arrive, all without ever being shot at. And if the strike is unsuccessful and the targets remain up, then run the fuck away before they can catch up thanks to your extreme engagement range. Try again tomorrow.

Crystal Chaff(Defensive System): It’s hard to dodge an Energy Projectile Weapon, and some of the special abilities Arlanian mechs are capable of using are ridiculously devastating. In the process of removing damaged bits of crystal and sometimes finding a crystal almost entirely destroyed, the Ravens have a supply of crystal dust that is generally no longer useful as a power source. But, with a few modifications, the Ravens have found it is useful as a kind of chaff against energy weapons and special abilities, as it tends to sponge up the energy, while also levitating in place to remain useful rather than just immediately falling. It’s also pretty darn useful for gumming up engines, slowing them down for long enough for the Ravens to get away. It also interferes with most targeting systems, including radar, ladar, infrared, and magic. If a group of Ravens decides to raid a location they think has energy weapons or any Arlanians, one of them having a few canisters of Crystal Chaff is almost a guarantee. Some of the most advanced cutting edge Raven systems are capable of dragging a cloud of Crystal Chaff around to maintain a shield for the Kensai. Obviously, this shield is not omni-directional, as otherwise the Kensai would interfere with its own engines and its use slows down the Raven while it drags the cloud.

Crystal Afterburner(Engine System): For reasons explained above, the Ravens have more damaged crystals than normal crystals, and one use they’ve found for them is as a sort of afterburner for their engines. Extremely bad fuel efficiency, but hey, when the other option is get torn apart by superior forces? Time to spend some cash and get out of there.