DNA Donors: Ho-Oh / Yanma
Fusion Name: Yan-Mo-Oh
New Types:
Base Stats: 85 / 100 / 67 / 100 / 99 / 101 [BST: 552] (+0 HP / +3 Atk / +0 Def / +8 SpA / +0 SpD / +9 Spe)
New Ability:
Mantodea = (Regenerator + Compound Eyes)
Ability Description: Combined effects.
Notable Moves:
Earthquake,
Flare Blitz,
Leech Life,
Sacred Fire,
U-turn...
Bug Buzz, Earth Power,
Fire Blast,
Overheat, Thunder...
Calm Mind, Defog, Roost, Swords Dance, Toxic,
Will-O-Wisp...
Intended Role: Physical Wallbreaker, Special Wallbreaker, Offensive Pivot, Setup Sweeper, Hazard Removal
Role Justification: Versatile regen mon that can pick and choose what it wishes to do with its balanced stats and wide movepool. Physical sets have access to Swords Dance and the strong Sacred Fire as its STAB, alongside a STAB U-turn and some good coverage in Earthquake. Sacred Fire in particular can very easily force progress, even if Yan-Mo-Oh isn't doing that much damage just purely off of that 50% burn chance, though it's lower PP means you have to be extra wise in choosing when you wish to use the attack. Special sets have the much weaker Calm Mind but can utilize better coverage in both Earth Power and Thunder that can go around the latter's accuracy problems with Compound Eyes. Additionally, Yan-Mo-Oh's unique defensive typing lets it be a decent switch-in with Regen, as it can come in well against the tier's Fighting-types, Grass-types, and Ice-types, such as the newly buffed Revarantis, as well as Primeleo. Lastly, Roost can allow it to spec into a more defensive build that utilizes it running perfect accuracy Will-O-Wisps and annoying the heck out of the tier's physical attackers.
Yan-Mo-Oh's biggest problem is it's typing, because although it is one of the better combinations for Bug-types, at the end of the day it is still a 4x weak Bug-type with a crippling weakness to Stealth Rock and practically required to run Heavy Duty Boots. This makes it especially vulnerable to Knock Off, which a lot of mons got after the Teal Mask DLC. Not only that but the mon's statspread, although good for allowing it to diversify the type of roles it wants on a team, leaves it unable to truly excel at anything, which means that it will sometimes feel as though the mon is either lacking in power, bulk, or speed, and unable to cross important benchmarks that other mons with their more specialized roles would usually be able to cross.
Offensive Pivot 
Yan-Mo-Oh @ Heavy-Duty Boots
Ability: Mantodea
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Sacred Fire / Flare Blitz
- Leech Life
- Earthquake
- U-turn
Strong STABs and a spammable U-turn are the hallmark of this set. Earthquake is there as important coverage to hit mons like Yu-Clod, Druddizor, Zarubok, and Bellikiss, as some examples. Leech Life could probably be substituted for a better attack, as Bug- STAB isn't that great on its own.
Swords Dance 
Yan-Mo-Oh @ Heavy-Duty Boots
Ability: Mantodea
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Swords Dance
- Sacred Fire / Flare Blitz
- Leech Life
- Earthquake
Swords Dance set that can use its good STAB moves to act as a good setup sweeper after it's checks are gone. Leech Life is a decent option here since it has a decent BP alongside the healing property that allows it to compensate for Flare Blitz's recoil damage.
Defog 
Yan-Mo-Oh @ Heavy-Duty Boots
Ability: Mantodea
EVs: 252 HP / 4 SpD / 252 Spe
Jolly Nature
- Sacred Fire
- Defog
- U-turn
- Toxic
A more defensively inclined Yan-Mo-Oh set that focuses on spreading status with Sacred Fire and Toxic, removing hazards with Defog, and a STAB U-turn to reliably chip opponents and gain momentum for the team. This set is a bit more shaky, but I'm sure we could do better.
Choice Specs 
Yan-Mo-Oh @ Choice Specs
Ability: Mantodea
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Fire Blast
- Bug Buzz
- Thunder
- Giga Drain
Special attacking set that utilizes Choice Specs. Coverage is practically perfect for the entire tier, as Giga Drain allows it to hit important Waters and Grounds. Attack power is higher than the physical set because you've got higher BP STABs in Fire Blast and Bug Buzz, and a much more powerful coverage option in Thunder to hit Flying-types.