The movie was in color.
What I remember is a white actor playing Merlin bit in modern time.
He bought a house far away from everything. When he bought it he persited to clean up the house finding a lot of weapons.
The next part I remember is when this princes is being chased by urk like creatures. She has 3 people by her side as one by one get eliminated by the urks. Then she enters a Portal to the time with the guy that supposed to be Merlin but after arriving he dies and later gets rivived by a native person telling him about the person who used to live in the house. Then he starts to set up a defense against the urks because the Portal only opens at a certain time for so long. Next a huge battle happens where urks are rushing through the tunnel with a dragon as the guy that supposed to be Merlin start to shoot them with a sniper set up on top off his roof. After he defats all the urks he has the dragon left which he get it to follow him while he is on a 4 wheeler. He enters the others side but there is only so much time left until the Portal closes, so he returns to his realm with enough time for the Portal to close decapitating the dragon.
PS: it was a movie.
That is all I remember