Lero is the Earl’s talking umbrella and golem, which appears as a normal cane umbrella with the addition of a small talking jack-o-lantern on the tip. It does not do much except for screaming around, adding its own name on almost every sentence said by it. When used by Earl, it works as a flying umbrella in the style of Mary Poppins. It’s very loyal to the Earl and likes to stay with him, but Road often takes Lero with her against Lero’s connivance. When in her usage, he acts as a witch’s broom and an umbrella. Lero also seems to be the holder of the Earl’s sword when it is not in use, as seen in chapter 79 when the Earl pulls the sword out of Lero while fighting Allen Walker. Additionally, the Earl used Lero as a beacon of sorts, as seen in Volume 1 when he used it to summon a swarm of Level 1 Akuma to attack Allen. Lero was also sent to kidnap Lenalee while she was in Edo and transport her to the Ark so she could be destroyed as it downloaded and collapsed. Lero ended up taking several other Exorcists along too. Right now, Lero is reunited with the Earl.
