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After a friend and I played the last week, he commented that there appeared to be no restrictions about a hero on a flying mount (barring a monster that flies and is amount) joining a unit.
That would let me Disc Riders of Tzeentch who are on warbeasts, which use cavalry rules when ridden, join a unit of knights, thereby granting them all the protections therein.
I went back and read what I thought were the pertinent sections and have to agree with him.
Thoughts? It sounds and looks odd but seems permissible.
I'll look up the page numbers when I get a minute.
Being the same troop type isn't an issue when it comes to joining a unit. A character of one type can join a unit of another; he just forgoes benefits like Look Out Sir! rolls when he does.
The only issue is there's a printed restriction on flyers joining units somewhere, which I can't find. It's one of those bits left over from 7th that's out the window, unless it's in the book.
If theres a rule that prevents joining monstrous cavalry (the flying kind in this matter) with normal units, i cannot find it.
only restrictions i see: Characters...
- can't join flying units,
- can't join any unit if it's riding a monster.
Warchief Diggah o da Bloodmoon Squiggahs
It seems ok to me for a Disc-rider to join knights... but I guess he would need to use a 'normal' (non-flying) move while joined to the unit. This is a slight inconvenience, as the Disc has a move of 1 (!).
Also, you're correct about using the lowest move value ( BRB p. 99 )