User blog comment:ClariS/My Champion Remake: Kayle/@comment-67.225.8.144-20120409053335

What about:

Intervention

(Active) Kayle sheilds the Target Ally, or herself, with holy light for up to 8s or blocking 300/550/800 (+1.0AP) damage. While the sheild is active, the Target does 10/15/20% (+0.01%AP) increased Attack Damage. (Active) While the sheild is active, Kayle may deactivate it in a massive burst of holy energy rendering the Target Invulnerable for 1.25/1.5/1.75s but partially Blinding them reducing Attack Damage by 25/20/15% (-0.01%AP) for the duration.

Cost: 100 Mana, then 75 Mana. CD: 90/75/60s