The Semi-Demi-God is a creature of semi-godlike powers, due to being an offspring of a non-godlike creature and a Semi-God, which is a creature that corrupts the Noble image of Gods. Examples of Semi-God powers include Thuz, a god that throws a hammer with the powers of static electricity, Ronan, conqueror of all Rune-like inscriptions (and would make them glow in weird ways for some rare artifacts), Triage, the Semi-God of rectangle designs, and Vorpal, the one who makes Lance's of wind and throws them around for fun.
If you see a Semi-Demi-God, impress him with your Semi-Godlike powers and he will accept you as a brother or sister. Don't think you have any? Never fear! Pretend that your power is in extreme inebriation, challenge them all to a drinking contest, then do something clever, like tiptoeing away.
If a Semi-Demi-God is attacking you, blow gently on him. He will think Vorpal is nearby and flee. Just make sure that the real Vorpal isn't nearby.