Djer was a Pharoah during the Egyptian First Kingdom, scholars have put his reign at roughly 3100 B.C.E to 3055 B.C.E. Methos betrayed Djer, poisoned him, and encased him in a sarcophagus until 2001 as revenge for Djer's 'Smiting of Sinai'. According to the the Methos Chronicles Methos then became the next Pharoah for an unspecified period of time.
When Djer was freed from his sarcophagus in 2001 he and Methos engaged in combat that was prematurely ended by the intervention of Dr. Mina Abadi and a museum security guard. Djer's fate is not explicitly stated as the Methos Chronicles abruptly ended after 8 installments. It is generally assumed that Methos took Djer's head.