[Nightengale]

Originally Posted by JanthraX^

Er now this might sound a tad bit stupid,

but can the masters use their spells through/on servants, for example, shirou uses 'reinforce' (i think its called ) on that poster can he do the same for saber?

Spoiler for minor spoiler:

Yes, Servants and Masters are capable of using magic to each other. Though, clearly not all magic can be invoked. Just like how Shirou cannot reinforce Saber with his magic, as his magic applies only to non-living objects.

Spoiler for game spoiler:

There's one part in the game where Caster casted a spell on his Master, making him capable of matching Saber with the Master's bare hands.