People who start fires intentionally are called pyromaniac or pyromania. These people are then most likely to start a fire by arson, in which they would then be considered arsonists.
you call them bitefull
belligerent
a traveller...
a geologist
Pyromaniac.
geek
a traveller...
sharp
There is no special name for a person who likes squirrels.
How about a "gun enthusiast"?
a troublemaker?
blademaniac