Susanoo Combat and Appearance

The Susanoo Combo

With any stage that has arms (stage 2 and up), left click no longer swings your hand: it drives the Susanoo's combo. Clicks 1-3 are strikes thrown along your look; click 4 is a slam.
Strikes: a 0.75-second animation, landing at 0.35 seconds. Everything in a 70-degree cone out to the stage's reach takes force damage (see the table below) and is flung sideways the way the arm swept, with sweep particles across the front.
Slam (4th hit): a 1.1-second animation, landing at 0.65 seconds. It crashes down in front (at 60% of reach), hitting everything within a radius of 3.5 + 0.9 x stage, plus 2.5 x (stage - 3) from stage 4 up, for 1.8 times the strike damage, throwing them up and back, with debris, dust and an explosion sound.
Full Body finisher (stage 6 slam): the great blade brought straight down, cleaving a long line ahead. Everything in a narrow 16-degree cone out to 1.25 times the reach (35 blocks) takes 2.2 times the strike damage, with dust, glow and debris along the line.
Timing: one click is buffered if pressed in the last half of an animation, so mashing flows. The combo starts over after the slam, or 1.5 seconds after an animation ends with no click.
Arms: the one-armed form (stage 2) uses its one arm for everything: a swipe, a backhand (swept back the other way, flinging targets the other way), a swipe and the slam (the left arm for Sasuke, the right for everyone else). Stages 3-5 alternate arms on the strikes and slam with both. The Full Body form cuts with its katana in both hands on every hit.

Strike Damage by Stage

Real damage per strike, before your Ninjutsu power (capped at 250 a hit like all jutsu damage):

Stage 2: about 62.
Stage 3: about 79.
Stage 4: about 96.
Stage 5: about 113.
Stage 6: about 129.
Slam: x1.8. Stage 6 finisher: x2.2.

How Each Stage Looks

Every Susanoo is sculpted from smooth swept shapes filled with mottled translucent chakra in the owner's colour, outlined in dark ink like the anime, with glowing eyes, wisps of flame and a haze of chakra. Its head turns with your look, and its arms play the combo.

Stage 1, Ribcage: broad banded ribs spiralling round you, open in front, on a spine with a collar of bone.
Stage 2, Ribcage With One Arm: a jointed arm of bone rising from behind the shoulder, with a heavy fist at its end.
Stage 3, Skeletal: a towering skeleton round you: ribs and breastbone, bolted shoulders, bony arms and hands, and a skull with burning eyes.
Stage 4, Humanoid: a muscled warrior of chakra rising out of a haze round you, with flame for hair and its weapon in hand.
Stage 5, Armoured: curved plate on chest, belly, back and shoulders, forearm guards, an oni's mask with fangs, a crystal on the brow, and horns.
Stage 6, Full Body (Perfect): the armoured warrior whole and towering on long armoured legs under a belted skirt of plates, with great gridded shoulder plates, vast feathered wings, and a long flame-wreathed blade held in both hands. Its user rides in the brow crystal.

Each Character's Weapons

Itachi (stages 4-5): the Totsuka Blade (a sake gourd held at its neck, with a long wavering blade of liquid flame pouring from its mouth) in one hand, and the Yata Mirror in the other.
Sasuke (stages 4-5): a great recurved bow of chakra with a string of light, and golden eyes instead of pale ones.
Madara, Obito and Shisui (stages 4-5): a sword held in the fist.
Stage 6: every character carries the great katana in both hands and has wings.
Sasuke's stage 1-2 Susanoo is wreathed in black flame while Kagutsuchi is active.

First-person View

You see your own Susanoo as a faint tint (28% opacity) so you can see out through it. Everyone else, and you in third person, see it solid.