It is generally considered canon unless contradicted in-game, in which case the game takes precedence.
Sir Frey, also referred to as Lord Frey, is an old and very strong knight of Varrock. He won an arm-wrestling match against Sir Theodore and was later challenged by Gar'rth, to whom he narrowly lost.
A few weeks later, Lord Frey led the defence of the northernmost bridge during the Second Battle of the Salve. When Tenebra and his forces weakened as a result of the strengthening of the River Salve, Frey and his forces were able to push back most of the undead.