Zinder is the god of desire and seems closely related to Zandroe, God of Greed. He is mentioned in the Covetous Gold Serpent Ring description and is a god one can affiliate themselves with when using the Name-engraved Ring.
Much like Zandroe, Zinder manifests as a serpent and his servants are also serpents. It may be that Zinder is a primordial serpent or that he is something greater, and orders primordial serpents.
Zinder and Zandroe resemble Kaathe and Frampt from the original Dark Souls game, in the sense that they are both serpents and seem to represent the same thing, yet with a different take on it.
Zinder is associated with desire, which is typically viewed as a vice. His description says that only a cowards see every chance as something to fear, and therefore implies that Zinder is not afraid to want something, despite what it may mean about him.
His symbol on the Name-engraved Ring is a pig's head which closely resembles the Porcine Shield found in the Iron Keep.