<Snipped quote by Dark Cloud>
I thought it was the gnomes that kobold had a mutual restraining order with.
Kobolds have an extreme hatred of gnomes because the gnome god, if I recall correctly, pulled a 'prank' on the earliest kobold society that took them from having the largest fortified civilization in the world, to where they are now.
As a rule, the majority of races look down on kobolds because they're essentially raccoons. They breed like rodents, they live in squalor, and they steal other people's trash because their culture teaches them that that's okay. For most races, the main benefit of having kobolds around is that they tend to fix random objects/tunnels/paths/buildings, often using tools made from repurposed refuse.
The problem between kobolds and dwarves is that dwarves are very particular about ownership, and will often repurpose their own refuse. So, stealing it isn't okay. More over, dwarves rarely need anything fixed, because they like to fix things themselves. When kobolds try and fix their stuff, it's more of a nuisance than useful, because they don't build up to dwarven standards.
Also, while most species are too big to fit into kobold tunnels, dwarves can fit into the bigger ones and it's often hard to tell the difference between an old, deserted kobold tunnel, and a fresh one. Old or new, they often have a great deal of traps in them, which are hazardous to dwarves mining those tunnels.
So, while most races will generally ignore kobolds until they make themselves an active nuisance, dwarves view them as more like a rat infestation. None of the goodly races actually see them, on a grand scale, as anything more than a monstrous race. So dwarves basically get a free pass to actively commit genocide against the little lizard-lings, and will do so whenever they find them in/on/near their homes. Thus, standard practice for dwarves is to kill kobolds whenever they see them.
Luckily, Einkil is not a normal dwarf. He's very much a hippy, by dwarf standards, and is happy to live and let live. However, he is still a dwarf, raised by dwarves with dwarven morals and ideals, and would not hesitate to kill what to him is essentially a vermin if it actively caused him problems.