So this is Merlin

I'm sure you all know his background as the wizard who helped out King Arthur. Well there's more to know about him for example his grand magic(s)

Merlin has 9 grand Magics that are available to him, he has the ability to unleash the power of the 6 main Excalibur's being Excalibur, Excalibur Morgana, Excalibur Vivianne, Excalibur tora, Excalibur galus, and Excalibur Mordred.  His other 3 grand other grand Magic's are Excalibur Merlin which he can only use after obtaining the other 6 excaliburs, understanding of the world, which allows him to obtain the 6 other Excaliburs, and garden of Avalon: sacred garden which allows him to open a reality marble with extreme healing properties.

Merlin is a high class caster but a caster none the less and while he is powerful a half-decent assassin or a fast warrior could take him down with relative ease thanks to his caster class squishy ness however he pairs well with most warrior class servants and with some other casters like semiramis, he can also work well with kiyohime.

His hidden abilities are also top of the line just like his grand Magics because they give him the ability to actually sustain himself without a master so if you kill his master you might actually be able to recruit him.

Overall Merlin is a squishy power house of a caster and should probably be paired with a defensive servant or one that can help him take out enemies quickly