This keyword was introduced in Call of the Crystals.

Haste is a keyword passive ability in Shadow Era (written in bold).

• Haste applies specifically to summoned allies.
  
• Haste allows for an ally with the ability to attack and use any abilities on the turn it is summoned, whereas normally allies are exhausted upon being summoned.
• Some allies have haste as one of their own abilities, other times they can be given haste by card effects.
• NOTE: haste does not apply to allies that are returned to play, so allies revived by Gravebone's ability won't be able to gain haste, for example.