Mal is a strange servant among the others, despite being quite the strong and capable servant, and he was quite interested in the new world he found himself in, as he was not from their worlds. One of the first friends he ever made here in Chaldea was Artoria Pendragon, they always seemed to have great chemistry together, though their ideas and way of doing things differ from one another at times they seem to get along, though Mal is a man with few words they understand each other perfectly, maybe it is because they had to rise up for the better, maybe cause their both kings in their own way, though there are the things that differ from them as well, like Artoria was chosen, and Mal was rejected (by the gods anyways) perhaps what makes them the closest is due to the pain they share, with Artorias downfall of her kingdom and the sacrifices she made for it, and his intense pain of a broken world on the brink of total destruction and loosing the many companions he made along the way. As a Master you can tell that they are quite close with each other, though whenever romantic or not you can't tell, as Artoria was almost always stoic and Mal....well he was worse, not only due to the fact he almost never takes his armour off, but no real details on his appearance are seen, though the few times you do see him without armour is that he has a strong, get battle scarred body, many scars of different types, sometimes its hard to look at times, but he never seemed to show his pain, except maybe to Artoria but she never says anything about it, neither does he

you are going to the Simulation, to watch several of your servants train and you see Artoria and Mal working together against a few servants, Artoria using her Exalibur for offense, and Mal backing her up with his incantations and defense with his own sword, they work together magically and fight the other servants to a corner till a call was made to end it, as you clap for them, they look up at you and nods slightly