Return to Prime (根幻回帰 ; kongengaiki) in a keyword introduced in BS52. Only the Reborn side of Rebirth X-Rares have this keyword, which is worded as follows:
- Return to Prime - When this card would leave the Field by opposing effects, you can flip and deploy it.
Much like Rebirth works as a stay-on-field effect, so does Return to Prime, looping the card's presence on the field and enabling multiple uses of (When Deployed) and (When Reborn) effects, for as long as the player's counters allow it.
Q: What is a Reborn Spirit's "Return to Prime"?
A: When the Spirit is destroyed, depleted, returned to hand/deck, sent to Removed Zone or banished by an opposing effect, Return to Prime allows the player to pay the cost to deploy the Rebirth Nexus. When doing so, no counters are gained, and effects affecting the Reborn Spirit are interrupted. Also, while the player cannot use its own symbol to reduce the cost when deploying the Nexus, cores can be moved to it, and its (When Deployed)/Core Charge effects can activate, as well as any other effects which trigger upon a Nexus being deployed.
Q: When you use the effect of your The HellDog Cerru-Berus to target the opposing The Red Divine Dragon Emperor and use it as your own Spirit, then during the Attack Step Emperor is destroyed, can its Return to Prime activate?
A: As you can't summon/deploy opposing cards on your Field, Return to Prime, being a deploy effect, can't activate. However, when you target Emperor and move it to your Field, it's treated as leaving the opposing Field, so the opponent can activate its Return to Prime at that moment.
Q: The Brave Reborn Spirit activates Return to Prime, when does the braved Brave become Spirit condition?
A: The braved Brave becomes Spirit condition before you summon the Spirit card via Return to Prime, so when paying the cost, you can use that Brave's symbol for reduction costs.
Q: When you activates Return to Prime of a braved Spirit, and choose to have to braved Brave remains on field, when does the Brave becomes Spirit-form?
A: Before you deploy the Nexus card through Return to Prime. Hence, you can use the symbol of the brave to reduce the cost for deploying the Nexus card.