During the Chtuhulu (no idea how to write that) incident, Rider says "Hey guys, I've got a RM with a huge army and I could do something with it!".
Then everyone knows about it and Assassin murders Waver when he's resting.
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Hem, can Servants fly/move through air when in spirit form? That's how Diarmuid gets on Lancelot's jet, right?
Spoiler:
That was actually brought up in FSN, after the church scene at the end of the Fate route:
"That was before we made a contract, correct?
The sheath is my Noble Phantasm. It does not exhibit its power as a Noble Phantasm until magical energy is channeled into it. You cannot obtain your immortality unless you make a contract with me."
"…Well, I am sure it will protect the possessor's life if any magical energy is in it, but it will be weak. I am sure fusing with the sheath was the only way to save a dying person."
Hence the "in the air". Unless they're not fast enough to escape?
And it'd be limited to opponents with little range, I guess.
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We have. Just before the thing about Gilgamesh not actually being the first hero, I think.
But now we're talking about flying away.
Spoiler:
I kind of get the idea that defensively the Bellerophon enhanced Pegasus was stronger then the chariot. There is some side material which suggests that the clash between Excalibur and ride was more even then it seemed. In other words, medusa might have had reason to think she could win the clash and break through Excalibur whereas iskander took one look at what was happening and realized he was hopelessly outmatched.
also, again, iskander was actually injured by the blast radius. The anime didn't portray that very well.