-Vessel of Lightning:
You were suddenly struck by unnatural electricity, or you'd expose yourself to it for training.
Either way, your Ki assimilated its properties and is now part of you.
The celestial fire of the skies is now yours to manifest.

Fulminating Aura

3rd-lvl Way of Thundercats feature

Your Ki changed into condensed plasma, nestling you:
.Resistance to lightning damage.
.Your attacks using Ki Points add 1d6 lightning damage.

Bright Ink

6th-lvl Way of Thundercats feature

The electrical ki gathers into tattoos that stick to your body, from head to toe.
Available twice per long rest for 6 min with 2 KP:

.+1 on your CA.
.Your walking speed is doubled.
.On a Critical, your attacks paralyse the targets.

.At lvl 11, available thrice per long rest with 3 KP.

Tonitruous Techniques

11th-lvl Way of Thundercats feature

The real strength of the Ink is found in these moves you learn.
Paralysis on a Critical is still applied.

.Electro-Rampage: (2 KP)
In your WK's reach with both action & bonus action, you cut multiple targets at once.
2d6 slashing damage per targets, up to 4 targets at once.

.Flower of Thunder: (2 KP)
You spin lightning bolts onto a double palm-strike.
6d4 bludgeoning damage, targets are repelled 9 ft/3 m back.

.Lightning Spear: (2 KP)
With a swift kick, you throw a barbed javelin.
1d10 piercing damage in a 29 ft/9 m linear range.

Flash War Cry

17th-lvl Way of Thundercats feature

Available once per long rest with 4 KP for 6 min.
Extension of the Bright Ink, it becomes 3-dimensional as a thin exoskeleton.
You gain an electrical halo on your back & you grow feline ears as horns.

.+2 on your CA.
.You emit bright light in a 19 ft/6 m radius.
.Your walking speed is tripled. You walk on all 4, like a cat/lion/tiger.
.Any liquid surface you touch conducts electricity.
.Anyone physically touching you receives 1d6 lightning damage.
.Your attacks are added 1d8 lightning damage. Headbutts do 2d4 piercing damage.

.As you become continuous electricity, you are intangible to physical attacks.
Immunity to non-magical damage & lightning damage.