Caesar, Sieghart

Sieghart was an elemental master who has the ability to control the forces of fire, earth, water, poison, lightning and to some extent space. He was loosely associated with Demon Card, in that it happened to assist his quest to "preserve time". According to him, the power of Etherion is a direct threat to time itself, and begins to target 3173 (a.k.a. Elie).

Sieg is a serious person. He is very adamant about his purpose of protecting the flow of time, and will do anything to fulfill that purpose. He lightens up considerably after protecting and joining up with Haru's group, but remains a reserved person.

The name means win/victory/triumph (Sieg) hard (Hart) in German.

It is later revealed that the skeleton guarding Resha's grave all along was in fact Sieghart himself, through the means of a time paradox. When Haru, Elie and Sieghart attempted to return back to their time-line from the world 50 years in the past, he had pushed the two into the wormhole to the future without returning himself. He had only then realized his pre-destined fate, that the skeleton he had always been seeing was none other than himself; he was to guard Symphonia and Resha's grave from Overdrive and the world with his life for the next 50 years, until the decisive moment where the trio would once again find his skeleton and return to the past (as they themselves had just done; maintaining the time paradox/time loop). He knew that he could not "change" anything in the past-timeline he had to stay in, as to not affect the flow of the world. So, he sat in front of the grave for the next 50 years, unmoving, unhindered, completely isolated from the world, and without food or water... nothing. His final words were, "I thought I could do nothing in this era, but there is still one thing I can do... I can protect Elie to the end, yes... don't you worry... I'll protect you with everything I have." Elie's necklace sparkled around his neck as he smiled for the last time.

When Haru and Elie appear back in their timeline, to their horror, they see Elie's necklace around the familiar skeleton's neck, sitting in the same position they last saw their comrade. That's when they realized.

It was also later revealed that sometime during his 50 years of isolation at Resha's grave, he foresaw some of the events in the future through the use of the wormhole. He would commit a taboo and interfere with the flow of time just once; through magic, he prepared letters to be sent to all of Haru's allies and friends to support him on the date of the final battle between Haru's team and Lucia's forces.

(Source: Rave Master Wikia)