Ruadan

Ruadan, portrayed by Liam Cunningham, will appear in Series 5. It is assumed from footage revealed that he will ally with Morgana Pendragon and from the dialogue opposes Arthur's reign. Katie McGrath, portrayer of Morgana, has described Liam's character as a "freedom fighter" in an interview at Comic Con.

Appearance
From the trailer, Ruadan was heard saying ''"Prophecies do not lie. Arthur's bane once known to us, his end is nigh." ''As the trailer only showed footage from the first few episodes of the series it is assumed he will appear early in the series.

Morgana is seen in one shot telling Liam to "Prepare for battle". It is assumed Liam is the leader of a force that opposes Arthur and will be involved in Morgana and possibly Mordred's schemes to bring down King Arthur, Queen Gwen, Camelot and those who oppose magic (Katie stated that Morgana's plans no longer revolve on taking the throne, but getting revenge on those who persecute magic).

Abilities
It is assumed Ruadan is handy with a sword, as he is scene weilding one in trailers. It is unknown if Ruadan possesses magical abilities, but it is likely he at least supports magic due to his alliance with the witch Morgana.