Note: I don't own anything
Idea №5 FMA:B (kinda) x Worm
Alt power Taylor
Taylor becomes a homunculus with all seven abilities + standard homunculus regeneration power, and a Striker ability that allows to suck out the life force out of other living beings to charge her philosopher's stone, the core of her being, or charge it by consuming food (which is way less efficient, especially because the food has to be actually digested, but much safer and humane). When using the homunculus abilities her mind becomes corrupted by the sins associated with that ability. Basically, if she uses the ultimate shield too much she becomes more greedy and etc.. To balance it out she would have to use other abilities more, which clears her mind and returns her to her default personality, whatever it may be at the time. Using the abilities also slowly burns through the stone's energy.
On top of all that she can also turn others into homunculi the same way Father turned Bradley into Wrath, except that they only get one weaker version of the seven ultimate abilities and can't recharge the philosopher's stone by consuming the life force of others (they have to either eat to recharge it, or Taylor can charge it up for them). Also, their minds are permanently corrupted by the sin that their ability is associated with, but not to the same degree as Taylors if she uses the abilities too much.