This Union Arena That Time I Got Reincarnated as a Slime special booster pack is a single sealed pack from the UE20BT set for Bandai's Union Arena card game. It suits players adding Tempest characters to a deck and collectors after the set's signature and alt art cards.

• Set: UE20BT, That Time I Got Reincarnated as a Slime special booster
• Contents: 12 cards per pack
• Rarities: Common, Uncommon, Rare and Super Rare, with Action Point cards at a low pull rate
• Lineup: 188 card types plus 13 Action Point card types, alt art versions included
• Featured characters: Rimuru, Milim, Shion, Benimaru, Shuna, Veldora and Diablo among others