Mathias has long light mint hair tied to a slightly loose side ponytail.
Mathias is shown to be kind and consedirate at first but in the Second Season, he kills the High Elder. He really loves the Holy City and refuses to leave causing him to do sinful actions. He then places an Artifact chip created by Erenfried on his neck to receive Purifying powers. Due to the chip, half of Mathias is controlled by a Thanatos. He is killed by Erebos when trying to protect Rene.