Might Guy
The Noble Green Beast. Youth never gives up! +5% speed. Below 50% health his hits deal +25% damage and the dash recharges twice as fast.
Jutsu kit
Kit jutsu show up more often on level up. Some are only learned later in the saga, as in the series.
You arrive with a flying kick on three nearby enemies and plow through anyone in between.
Open the gates. A shockwave, then +25% damage and +15% speed for a few seconds.
A punch so fast it compresses the air into a tiger that smashes everything in a straight line.
Invisible punches fall like elephant feet where the enemies are thickest.
Plus every Academy jutsu: Shuriken Kunai Shadow Clone Jutsu Poisoned Senbon Paper Bomb Kunai Kunai Rain
Secret technique and evolutions

Secret technique: Supreme Leaf Hurricane

+20 health, +6% speed, +15% damage
Secret technique: Daytime Tiger

+30 health, +8% speed, +30% damage
Secret technique: Night Guy
Forms change with the saga
Some evolutions change look as you move forward in the story. Level and bonuses stay the same, while title, sprite and secret technique change.
Lv 10

Secret technique: Morning Peacock

Secret technique: Daytime Tiger
Lv 20

Secret technique: Daytime Tiger

Secret technique: Night Guy
Secret techniques in action
Every form has its own secret technique, with its own effect. The strike hits every enemy around the ninja.
7 costumes: you'll find them with their conditions on the ninja's sheet, in the game. The almost-ready ones are in What to do now.
Possible combined jutsu
Fusions Gai can obtain alone at the Seal Altar.
Build tips
His kit's natures: Taijutsu.
Tools that boost the kit
Sensei of Team Guy: after chapter 1 if it's your team, otherwise with the Bell Test when you have all their genin