No, we wont use the Evil Twin engine for Melffy of the Forest, as the payout for it is super weak, but we still can tho lol. We use the engine for card advantage and interruption with the Kisikil Lilla extra deck monsters. Start with Live Twin monster, make Evil Twin Kisikil, revive Live Twin, make Evil Twin Lilla, revive Evil Twin Kisikil for draw, make Evil Twin Kisikil again so we can summon Evil Twin Lilla during opponent's turn for free pop. Turn 3 we can trigger both the draw and pop. If we have Puppy in hand, we can summon it during the end phase. Monster Reborn allows us to link climb for Unchained Abomination because it re-summon Evil Twin Kisikil.
Obedience Schooled combo is what we do to utilize Melffy the best. By summoning
Melffy+Kalantosa+random (the random can be another Melffy, since we only run small pool of beast) will have 2 interruptions right away. If we draw Kalantosa, we have to summon Fenny instead of Puppy. Make Melffy of the Forest using Melffy + random, use Forest detach Melffy add Melffy Tag, use Tag ss Melffy, make Excited Melffy. During opponent's turn, we can use Excited to re-summon Melffy and Kalantosa, making us can trigger 2 Kalantosa.
Main Deck: Evil Twin engine, 12 starters (3 Kisikil, 3 Lilla, 3 Entrance, 3 Cynet Mining). 3 Melffy Puppy (best Melffy, 3 because you wanna see it the most together with Evil Twin engine), 1 Fenny (for Obedience Schooled play), 1 Tag (combo piece, extender), Hide-and-Seek (protection and recursion, because we play control). 2 Kalantosa (Melffy partner in crime, 2 because you can trigger both) and 1 Valerifawn (can re-summon Kalantosa and triggering it, also as extender for follow-up). 3 Obedience Schooled (best Melffy starter lol). Monster Reborn for link climb/xyz material. The rest is just staple.
Extra Deck: 3 Kisikil and 3 Lilla (play the most copies as spare). 2 Forest (generic, gives plus) and 1 Excited (combo piece, also allows Negalogia play). Unchained Abomination and Knightmares are just generic good fiend extra deck monsters. Sky Cavalry Centaurea (great rank 2 xyz with non-target, non-destruction removal, and allows Negalogia play) and last but not least, Negalogia (wipe boards).
Pros: Super consistent in putting 2 interruptions, big staples.
Cons: Low atk problem.
Cards to think of: Melfy Catty + Hop Ear Squadron (Catty returns to hand to add Hop Ear, it means Catty-Hop Ear cant work by themselves, so I cut it), Nimble Beaver or other rank 2 engine (good but as I stated Melffy of the Forest turbo is weak after testing), Tribrigade (eats resource too much and requires beast discard, we don't wanna discard our Melffy), Melffy Playhouse (possible multiple interruption, but is a win-more because Puppy and Obedience Schooled already do the same), other Melffy monsters (don't do much as Puppy/Fenny).