Seichiro Sakaki is his real name but you don't hear it much in the series. Everybody tends to just call him "Chief" or "Old Man". He is the head of the SV2 maintenance squad and it is he who could actually be considred to be in charge. Though not very outspoken he nonetheless does better than anybody elso could possibly hope to at maintaining labor which are constantly coming back with missing heads and limbs.
Shige Shiba is Sakaki's right hand man. He is the secon in command of the maintenance squad and is a bit of a genious. He become overwhelmed when he is told that he will one day succed Sakaki and this is understandable, who wants to live in a shadow that large!
Alphonse is Noa's labor. To most people he may just be a machine, but to Noa he is more than that. His name pops up so often, he deserves credit as a character.