Summons return in this game as
Eidolons, linked with the powers of the l'Cie. Confirmed summonable summons are
Shiva Sisters,
Odin,
Bahamut,
Alexander, and a new summon,
Brynhildr, while
Ifrit,
Carbuncle and
Siren have been announced to appear in
Final Fantasy XIII but haven't appeared as playable. All Eidolons have been given futuristic designs and the power to change their shape. The Eidolons are used both in battle and as plot devices in cutscenes. Each character has only one Eidolon, and Eidolons replace the other party members besides the summoner when called. Instead of HP, Eidolons use "Summon Points" (SP) to indicate their health, but SP also slowly decreases over time. Once SP is completely depleted, the Eidolon will disappear, and the other party members will return.