The Master Trickster (CR25/MR10)

This small being appears like a halfling male with brown eyes, brown short cropped hair, wearing black leather armor and wielding a halfling sling staff. As you watch him, he smiles and disappears right before your eyes.

XP 1,638,400

CG Medium male outsider (mythic, native) Spell Thief 20/Trickster 10; Master Rogue template 

Init +28; Senses blindsight 60 feet, darkvision 120 ft., low-light vision,