Assist

Assist is a keyword ability introduced in Battlebond that lets other players (normally your teammates) help you to cast spells. The helping player may pay up to the total generic mana part of the casting cost. The Assist mechanic was designed by Gavin Verhey.

Rulings

 * Players can't help with the colored mana requirements.
 * After you've revealed the card with assist and made all other required choices, including targets, then you can choose the player that will help you. This way the other player will know what they're signing up for.
 * If the chosen player doesn't want to pay, you can either pay the full cost yourself, or choose to back up and not cast the spell at all.