212.9c.

Planeswalker subtypes are always a single word and are listed after a long dash: "Planeswalker — Jace." Each word after the dash is a separate subtype. Planeswalker subtypes are also called planeswalker types. Planeswalkers may have multiple subtypes. (You can find the complete list of planeswalker subtypes under "Planeswalker Types" in the glossary at the end of this document.) If two or more planeswalkers that share a planeswalker type are in play, all are put into their owners' graveyards as a state-based effect. See rule 420.5.