Constantine 1×01: Non Est Asylum.

Demon seal designed with the Triangle of Solomon, Elder (Futhark) Runes, and Enochian scripts.

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Update #1:

(Clockwise, from the section nearest the bottom of the picture)

Raido – Jera – Othala – Uruz – Ansuz – Kenaz – Tiwaz – Othala – Tiwaz
(R J/Y O U A K/C T O T)

Sowilo – Isa – Othala – Nauthiz – Othala – Uruz – Ansuz – Mannaz – (can’t make it out) – Raido – Othala
(S I O N O U A M __ R O)

Isa – Sowilo – Uruz – Mannaz – Mannaz – Othala – Nauthiz – Jera – Othala – Uruz – Dagaz
(I S U M M O N J/Y O U D)

*I see a “I summon you” in the 3rd section;
* I see another ‘you’ in the 1st section
* I see an ‘act’ after the ‘you’ in the 1st section)

Update #2 with thanks to abs0luteb4stard:

The center sigil is for Furfur:

‘Furfur’ or ‘furfures’ in Latin means “bran”. However it seems more likely that the name is a corruption of ‘Furcifer’ the Latin word for scoundrel. a powerful Great Earl of Hell, being the ruler of twenty-nine legions of demons. He is a liar unless compelled to enter a magic triangle where he gives true answers to every question, speaking with a rough voice. Furfur causes love between a man and a woman, creates storms, tempests, thunder, lightning , and blasts, and teaches on secret and divine things.

Update #3 with thanks to iliumtwins:

I checked my copy of the Lesser Key of Solomon and lo and behold there it was! And they also describe the way he looks: appearing in the form of a heart with a fiery tail. Also, if you get him into the magic triangle he can change his form into that of an angel when bidden. Both of my copies of the book say 26 legions of spirits, but Wikipedia says 29 so…..