No, you will not take damage. Becoming "cast" is the last step in casting a spell, and this is when cast triggers go off. Since paying costs, which in this case includes the sacrifice of Ruric Thar, comes before that, he is not on the field anymore and cannot trigger.
I guess I am a little lost as to when he is no longer in play and what he sees as he goes out.
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[Modern] Allies
Former Rules Advisor
"Everything's better with pirates." - Lodge
(The Gamers: Dorkness Rising)
"Any sufficiently analyzed magic is indistinguishable from science."
(Girl Genius - Fairy Tale Theater Break - Cinderella, end of volume 8)