personal imagination about some touhou character's special moveset ideas
Well...if we're doing this...
Sakuya
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A button playstyle: Aerial combat is primary focus, not as good on the ground.
Neutral B - "Silverbound" (Creates a ring of knives around Sakuya, bounces off of floor and walls) (1% per knife, little knockback)
Side B - "Killer Doll" (Throws a glowing large knife that homes in slightly on nearest opponent, explodes into energy) (8%, high knockback)
Up B - "Shadowstep" (Sakuya steps on a knife platform and jumps high, double jump renewed afterward) (No damage, meteors upon high jump if opponent is under knives)
Down B - "Private Square" (Square reflector forms around Sakuya and follows her, when hit with a projectile, breaks into shard-like projectiles) (3% per shard, little knockback)
Super Move/Final Smash/Whatever: Eternal Meek (Fires large and fast random bullets for about 7 sec.) (5% each bullet, high knockback)
Youmu
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A Button playstyle: High damage sword usage, aerial combat is bad.
Myon is similar to Rosalina's Luma in Smash 4, attack consists of an energy ring (3% per Myon hit)
Neutral B: Myon Lock-On (Myon moves towards the opponent)
Side B: Karmic Punishment (Dashes to the side very fast, bullet trail deals damage) (Dash: 7%, Trail: 2% per bullet)
Up B: 2000 Yojana in One Slash (Bullet appears over Youmu, Youmu slashes upward and destroys bullet) (Slash: 8%, high knockback)
Down B: Myon Recall (Myon returns to following Youmu)
Super Move/Final Smash/Whatever: Konpaku's Ultimate Slash (30%, high knockback)
Komachi
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A Button playstyle: High damage in air AND on land, slow movement speed
Neutral B: Yesterday's Pay (Throws coins at the nearest opponent) (2% per coin)
Side B: Higan Tour (Moves horizontally in boat) (Deals no damage)
Up B: Spacial Thrust (Slashes downward which moves Komachi upwards, blast of wind below) (Slash: 7%, Wind: 2%, medium-high knockback)
Down B: Game of Life (If in grabbing range of opponent, swaps Komachi and opponent's damage percentage) (Damage and/or healing varies)
Super Move/Final Smash: Higan Retour (Sucks in opponent, Komachi spins and throws opponent upwards and to the side) (20%, high knockback)
These are just a couple ideas, similar to Peachems' post.