I have Beastman Shaman in game and i play Blood Summoning and corrupt 4 unit.

I can draw 4 or 1 card?

sorry for the bad english

Thx.

4 cards.

Since Beast Shaman says "When a Chaos unit you control is corrupted..." it triggers on each individual unit being corrupted.

If it were worded "When one or more Chaos units you control become corrupted..." then you would only get 1 card because it would be triggering on each action that corrupts units as opposed to each unit being corrupted.

Make sense?

Yes, sorry for the wrong place