A little bit of behind-the-scenes insight: had initially planned to have Drax's invisibility as a ridiculous Easter egg in his kit, but when I couldn't come up with a good signature ability I moved it there. However, I couldn't have a ridiculous joke ability as his signature ability, so I tried to put some more thought into it and actually make it viable. But if someone wonders why I let a throwaway joke be the signature ability in his kit, that's the reason for it.

Signature Ability - Master of the Hidden Arts

If the opponent has at least one Bar of Power and neither champion has landed a hit for 7 seconds, Drax places a Taunt Debuff on them for 5 seconds. If the opponent activates a Special Attack during this time, Drax goes invisible and places a Falter Debuff on them for the duration of the Special Attack.

For every hit the opponent Misses, Drax gains a 3-second Fury Buff. If he punishes the Special Attack, each Fury is turned into 7% Power

Cooldown 25 seconds.

Family of the Galaxy - Pre-Fight Ability

Drax has a Pre-Fight Ability that is dependent on which fellow Guardians of the Galaxy teammates he has by his side. Each member grants their own ability and he can choose one each fight, or two if fighting a #Villain. He cannot activate his Pre-Fight Ability against Mystic champions.

Agent Venom: 100% chance to shrug off a non-damaging Debuff whenever he activates a Special Attack, with it turning into an Aptitude Buff increasing the potency of any Fury and Precision Buffs by 15% for the duration of the Special Attack.
Gamora: The chance to gain Fury Buffs from landing basic attacks is increased by 3%, and each Fury Buff lasts 3 seconds longer.
Groot: Groot’s gentle nature grants Drax increased Energy Resistance and Physical Resistance during the opponent’s Special Attacks.
Star-Lord: Each hit in the combo grants 2% increased Critical Rating during Dashes and Special Attacks.
Rocket Raccoon: Utilizing a spare set of Rocket’s explosives, Drax can detonate any Armor Break effect on the opponent if he lands a Dash attack. Any detonated Armor Breaks deal Incinerate damage over 4 seconds.

The Destroyer - Passive

When Dashing toward an opponent, Drax gains a 30% chance to Glance their Ranged Attacks. This is increased to 70% when fighting #Villains, and 100% when fighting #VillainsOfTheContest champions.

Against Tech champions, this chance is increased by a flat 30%. Mystic champions cannot be Glanced unless they are tagged as #VillainsOfTheContest.

During this Dash, Drax is not interrupted by Glancing Attacks and automatically converts any damaging Debuffs on him into Fury Buffs.

If a #Villain activates a Special Attack during this Dash, the first hit has a 35% chance to Glance. If it does, Drax gains a 1-second Unstoppable Buff.

All Attacks

Drax has a 12% chance to gain a passive Destroyer charge whenever he hits the opponent with a basic attack. All of these charges are converted into 15-second Fury Buffs the next time he activates a Special Attack. If he is hit by a Special Attack before that happens, half of them are converted into Regen Buffs with each healing 3% health over 5 seconds while the rest of them are lost.

Should Drax reach 5 Fury Buffs, he also gains an indefinite Precision Buff. Max 5 Precision Buffs.

Critical Hits

Inflict a Bleed on the opponent. For every Precision Buff on Drax, there’s a 20% chance to inflict a Critical Bleed instead. Should the opponent be a #Villain or a #VillainOfTheContest, these Bleeds count as passive Debuffs.

Heavy Attacks

Armor Breaks the opponent until they launch their next Special Attack.

If there are Bleed Debuffs on the opponent, Drax has a 20% chance per Fury Buff to refresh them, as well as a 10% chance per Precision Buff to convert them into Critical Bleeds.

Special 1

Inflicts 3 Critical Bleeds and refreshes all Bleed effects, including Deep Bleeds.

Special 2

Drax inflicts a Deep Bleed Debuff on the opponent lasting 15 seconds. While it is active, subsequent Bleed Debuffs do 15% more damage and have 20% increased duration. Drax also gains a passive Aptitude Buff that increases the potency of his other Buffs by 30%.

Special 3

This attack does 75% more damage and inflicts 1 Critical Bleed per Guardian of the Galaxy member on the team.