So, I've been designing an alien species, actually a redesign of something from childhood. However, I've recently come into an issue with its limbs.
The creature possesses two arms. The right arm is roughly humanoid, ending in a prehensile hand. Currently, there are eight digits, although this may be subject to change. However, the left arm ends in a hand that has been modified into a weapon. Currently, four digits have been adapted into spikes, similar to Iguanodon, and the remaining four have modified into a thickened, blunt structure, leaving the entire hand to somewhat resemble a spiked mace.
However, this is where I've run into a roadblock. This is a naturally evolved creature, but I'm struggling to figure not only the circumstances for this adaptation but also if this level of asymmetry is really realistic.
EDIT - A few additional points to help clarify things. The species is sapient and civilization-faring. The eight digits are an attempt to get around the dexterity problem of only one functional hand, essentially putting two hands on one arm. Secondly, both genders possess this feature. Part of me is thinking to just go the Hellboy route.
Any answers would be greatly appreciated.