Hollow King's Armour

The Final Sword chewed through his barrier in seconds, and her heart dropped. Dross hadn't been able to persuade him either.
This was not how she wanted to win her crown.
The last of the barrier shattered, but as soon as she was through, her blade clanged against something solid. And stopped.
The sword Wavedancer. Its broad blue-tinged bulk hovered over Lindon like a second shield.
But it could only block so much. A waterfall of silver power still thundered down onto Lindon, washing over the flying sword.
Her feet only touched the ground as her technique began to fade, and she pulled her master's blade away. The sword-light died. For an instant, she expected to be jerked away from the arena instantly, her anger still unsatisfied.
Then she realized Lindon's presence hadn't disappeared.
A solid turtle's shell rushed at her chin. Yerin caught it on one of her sword-arms, but Lindon had anticipated that. He pivoted into her, plunging his white fist into her gut.
Breath rushed from her lungs and she flew back, head ringing. Her spiritual perception caught the madra lingering around his skin, and she realized what he'd done. He had blasted pure madra from all over his body, covering him in an inch of spiritual armor. Eithan's technique.

Uncrowned (Cradle Book 7)

The Hydra sent out a wave of death madra, but it still screamed from three throats as the barrage of techniques tore its body apart.
Not as much as it should have been torn apart, though.
...
And that was the moment when Lindon took the enemy seriously.
He dropped Blackflame and switched to the Path of Twin Stars. Little Blue cleansed her own channels at the same time, snapping the thread, but she was already weaker.
He surrounded himself with the Hollow Armor, letting the death madra wash over him, and landed on the body of the snake.
Then he slammed his palm down on its scales.

Reaper (Cradle Book 10)