So back when Infinite Fusion first came out, Nikon started designing a Vaporeon/Gardevoir, but wanted a few more parts from other mons involved. "Well at that point you already have 5 Pokemon involved, why not get a 'Full Team' Fusion together?" And that's how his Lilith came to be. I had to do the same with some of my favorites. Misdreavus, Sneasler, Emboar, Corviknight, Golurk and Metagross is what makes up Nikita.
I went a bit overboard in creating her "Dex Entry", but here's how I came to it: 3 Types, whichever is the most prominent. In Nikita's case, she's got 2 Steels (Corviknight and Metagross), 2 Fightings (Sneasler and Emboar), and 2 Ghosts (Misdreavus, and Golurk) 3 Abilities, only One is active at a time, and you can chose the ability that fits with the type. Base Stats: 610, adjusting how you please. (A Better way would have been combining the base stats of the 6 pokemon and then dividing by 6. Ah wells) 12 Moves, 2 per pokemon. Having a full set of 24 moves when your team doesn't have to Switch Out seems like a decent balance. Strengths and Weaknesses, I tried my best according to the usual Rock-Paper-Scissors, but having 3 types makes that a smidge harder to calculate.
I've built her up to be fairly tanky. She's got the One special move so she has some range, but otherwise she likes to get in Close and Personal for combat.