What Is Spear Wielding General Weak to?

Neither has any weakness but the Guard Dog of Hades will drain Fire and the Spear-Wielding General will drain Electric, Dish out as much damage as you can while keeping your health up.

Does akechi have weaknesses?

Akechi will summon empowered minions that you have seen before. They hit harder and do not have any weaknesses. Rather than dealing group damage, focus on taking one down and then move on to the other.

How do you kill Cendrillon?

Boss Battle: Cendrillon and Evil Synthetic Organisms

The synthetic organisms are weak to Nuclear so having Joker cast Freidyne is a good start. Once downed, use your strongest attacks to eliminate it so as to stop Cendrillon from receiving any support. Down Shot is an option if you don't have access to Nuclear skills.