Mr Mythen, 39, of Leckview Cottages, is still fighting for his life at the Royal Victoria Hospital after sustaining horrific head injuries in a hammer attack in Derry City.
Another man, Paddy Harkin, died during the attack at Bayview Terrace in the early hours of Sunday morning last.
Paul Greatbanks of Bayview Terrace in Derry appeared at Derry Magistrate Court charged with attempting to murder Mr Mythen and murdering Mr Harkin.
He spoke only to acknowledge his name during the brief hearing.
A police officer said she believed she could connect Greatbanks to the charges.
There was no application for bail and Greatbanks was remanded in custody to appear again by videolink on March10th.
There was a large crowd of family and friends of Mr. Harkin in court and District Judge Barney McElholm said he wanted to express his condolences to the family.
Letterkenny man Paul Mythen is well-known in the alternative arts scene around Letterkenny and Derry where he was part of the nartystation.com movie company.
He has starred in 16 of the group’s films and also played guitar.
Formerly of Croagh Patrick Avenue, his sister Clare is at his bedside in hospital as he battles to overcome his injuries.