Across all cultures throughout the world, there are numerous legends and myths about serpents. In almost all sources of mythology (except the Bible) the serpent is regarded as a being that holds great knowledge and insight. It is also related to renewal (shedding of old skin). Other sources portray the serpent as a "defender" (such as Mucalinda who guarded Buddha) because of the way they fan themselves out in defense while holding their ground.

I believe a serpent being would fit in well with the mythological based theme of demigod, preferably in the form of a Naga...A being with a serpent lower body and a Humanesque upper torso.

I think it would fit more as a General than Assassin

As for abilities:

1) There should definately be a line that increases XP gain with the final one possiby increasing MAX level by ~3-5.

2) A move that converts the enemy units into friendly units, with the possibility of turning minions at higher levels.

3) Move centered around shedding skin that adds more effects the higher the rank, i.e. removes debuffs, heals, modifies armor , increases speed. (think of it as a possible, "get out now"/"live to fight another day" button).

4) A move based on venom, i.e. single unit paralysis, blindness (aoe spit/ranged attack?),etc

5) A coiled strike attack that has a bit of leaping range to it (possibly can be merged with single unit paralysis venom above).

6) Aura for passive defense, attack, HP, and/or evade to minions

7) A tactical mastery upgrade line that increases Line of Sight and possibly adds cloaking.

8) Standard Morale boost upgrades

Ideally, this demigod will rely on its minions to kill the player, and use moves that put the other player in a state as to allow the units to actually hit the enemy (stunned, paralyzed) while doing little damage itself.