High Speed Seal (神速封印, Shinsoku fūin) is a keyword which debuted in SD35. The only spirit to possess it is The RabbitTwelveGodKing Mistral-Bit. The keyword's text reads as a combination of the text found on Seal and High Speed:
- High Speed Seal (Flash) - This spirit card may be summoned from your hand during Flash Timing. In that case, the cost of this spirit and cores to be put on this spirit must be paid or moved from your reserve. Afterwards, send (Soul Core) from one of your spirits to your Life.
This effect allows the player to make use of Seal during their Main Step and either Attack Step, giving them more freedom and possibly startling their opponent.