D-13

D-13 is the second playable ship in the game. Its capabilities are equal to those of Null, the difference between the two ships being entirely cosmetic. Like Null, its default weapon is the Peashooter.

Story
D-13 is the 13th Visitor of the Facility, and enters with their rival Null. Their progression through the Facility has them tailing Null, encountering more deadly versions of each boss, and finally catching up with Null at the Power Eternal conduit.

Upon meeting up with them, Null proceeds to transform into Monolith and begin its assault on them.

After defeating Monolith, D-13 destroys the conduit and exits the Facility, landing on a hillside beside a now broken Null.

Trivia

 * D-13 is named after the team that made the game: Team D-13. The ship is also used by them as a mascot of sorts.
 * D-13 shows up in The Binding of Isaac: Repentance as a co-op baby.