Deathbellow Raider — ruling 1

You still choose which player or planeswalker Deathbellow Raider attacks.

Deathbellow Raider — ruling 2

If, during your declare attackers step, Deathbellow Raider is tapped, is affected by a spell or ability that says it can't attack, or hasn't been under your control continuously since the turn began (and doesn't have haste), then it doesn't attack. If there's a cost associated with having a creature attack, you're not forced to pay that cost, so it doesn't have to attack in that case either.

Deathbellow Raider : règles, fonctionnement et interactions (MTG)

Deathbellow Raider 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

This creature attacks each combat if able. : Regenerate this creature.

How it works : Deathbellow Raider

Original English text — Wizards of the Coast / Scryfall

#1September 15, 2013· Wizards of the Coast
You still choose which player or planeswalker Deathbellow Raider attacks.
No other card is named in this ruling.
#2September 15, 2013· Wizards of the Coast
If, during your declare attackers step, Deathbellow Raider is tapped, is affected by a spell or ability that says it can't attack, or hasn't been under your control continuously since the turn began (and doesn't have haste), then it doesn't attack. If there's a cost associated with having a creature attack, you're not forced to pay that cost, so it doesn't have to attack in that case either.
No other card is named in this ruling.