RO-Z67/Legends

R0-Z67 was a nanny droid used by Darth Sidious during the Clone Wars.

Biography
In Sidious' secret facility on Mustafar, R0-Z67 tend to Force-sensitive children, kidnapped by Cad Bane to be raised and trained as part of Sidious' army of spies and assassins. When the facility was discovered by Jedi Knight Anakin Skywalker and his Padawan, Ahsoka Tano, Sidious via hologram ordered the droid to evacuate the children to another location and then to disable the facility's gravity support, letting it sink into lava. However, the Jedi managed to rescue the children from the droid and depart before the facility's ultimate destruction, leaving R0-Z67 to be destroyed in the lava.

Behind the scenes
The droid is referred to as both "R0-Z67" and "RO-Z67" in the according Episode Guide. Which designation is correct, remains unclear.