[viasta]

I dont see suzaku listed in the male set
and likewise dont see thundergod in female set
but females get a pretty butterfly and jade rabbit sets

also interesting page of the 9 Pet Type Pentagram
if you hover over a species the pink arrow means that its weak to whatever is on the other end and the light blue means that its strong against whatever is on the other end
red means that the two are natural enemies
not quite sure what the blue is suppose to be....
the species in clockwise order:
demon beast, sky/fly, underworld/dark, metal, humanoid, poison, wood spirits, elemental, and dragon

Pink arrows means whoever type is pointed to is weak against the one that is pointing. e.g. 天空(Sky/Air) is weak against 妖獸(Beasts).
Light Blue arrow shows that the type pointing is strong against the type being pointed. 妖獸(Beasts) is pointing to 天空(Sky/Air), so 妖獸(Beasts) is strong against 天空(Sky/Air).
Blue arrow means whoever it is pointing to the other type is super effective against it. e.g., 妖獸(Beasts) are most effective, super effective, against 木魔(Wood or Plant, both work).
So that makes 妖獸(Beasts) being least effect against 木魔(Wood/Plant). Thus 木魔(Wood/Plant) becoming 妖獸(Beasts)'s Red Arrow target.

Edit: Red arrow target, the one being targeted, is not very effective against the one that is pointing to the target.

Koa's explanation is weirdish :/, since there are two ends to arrows, etc.