Tenacity
From Inkipedia, the Splatoon wiki
With Tenacity, the special bar automatically fills anytime your team has more inactive (waiting to respawn) players than the enemy team. The gauge fills faster the greater the disparity is between the teams. This ability is restricted to headgear as a main ability.
In-Depth Ability
Use
Tenacity is an automatically activated ability that is triggered if all your team mates except you are splatted. This will instantly fill your special gauge up allowing you to fight back by avenging your splatted team mates. Although it can sometimes activate at times this can allow you a big chance to get back at your enemy.
Gear
Tenacity is the main ability of: