Over the years the Knight and Mage have been seen as direct opposites and classes that people would never find anything in common with each other. However, even in the historical stories like King Arthur, we see that there is a great respect for each other's skills and talents between the two classes.
Merlin the mage is Arthur's tutor and deepest friend. They respect each other greatly and have great power in what the other lacks. We see a great strong friendship between Steiner and Vivi which they admire each others talents and recognise each other's ability.
It is also interesting in the relationship of names that Merlin, as an older man fell in love with a woman called Vivian.