Volt

Volt is the spirit of electricity. He is one of the few, if not only, Summon Spirits that cannot communicate in English.

Role in Tales of Symphonia
Volt was the first spirit Sheena attempted to pact with when she was young. The pact failed, and ended up harming many people from her hometown. Although she's terrified of it now, Sheena has to meet him again alongside Lloyd and his pals in order to gain power to travel between Sylvarant and Tethe'alla. Although the spirit is tamed this time, it came at an awful price; Corrine sacrificed its life in order to prevent it from killing Sheena. After her adoptive grandfather, the chief of Mizuho awakens in a side-quest, she says in a Z-Skit that she and Volt may now be able to become friends.