extra slotA Sonic 3 A.I.R. (S3AIR) Mod in the Extra Slot Characters category, submitted by The sonic theory. Ads keep us on. Without them, we wouldn't exist. We don't have paywalls or sellThis extra slot is one level lower than the hhest-level spell you can cast. For example, a 6th-level sorcerer gains an extra 2nd-level slot. Once selected, the extra spell slot never changes