Comeuppance — ruling 1

Comeuppance's effect is not a redirection effect. If it prevents damage, Comeuppance (not the original source) deals damage to the permanent or player as part of that prevention effect. Comeuppance is the source of the new damage, so the characteristics of the original source (such as its color, or whether it had lifelink or deathtouch) don't affect the new damage. The new damage is not combat damage, even if the prevented damage was.

Comeuppance : règles, fonctionnement et interactions (MTG)

Comeuppance is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Prevent all damage that would be dealt to you and planeswalkers you control this turn by sources you don't control. If damage from a creature source is prevented this way, Comeuppance deals that much damage to that creature. If damage from a noncreature source is prevented this way, Comeuppance deals that much damage to the source's controller.

How it works : Comeuppance

Original English text — Wizards of the Coast / Scryfall

#1November 7, 2014· Wizards of the Coast
Comeuppance's effect is not a redirection effect. If it prevents damage, Comeuppance (not the original source) deals damage to the permanent or player as part of that prevention effect. Comeuppance is the source of the new damage, so the characteristics of the original source (such as its color, or whether it had lifelink or deathtouch) don't affect the new damage. The new damage is not combat damage, even if the prevented damage was.
No other card is named in this ruling.