OH BOY, you ask the COMPLICATED questions, don't you? xD<br/><br/>Ok, well. The answer really comes down to DC's complicated shit to do with Hell. See, whilst they share a Multiverse - and people like Zatanna and Constantine have been to the Vertigoverse before - Prime, Earth and Vertigo don't ever really interact that much, since DC doesn't want kids accidentally picking up their more "adult themed" comic runs. Hell in Vertigo is a completely separate entity to Hell in the wider DC-verse, so Lucifer in Vertigo has never (that I know of) actually MET any of the Demons from Earth 1 / Prime / etc. Complicating matters further is that Trigon is<em>technically</em>not a demon, and actually rules his own conquered realm that is separate from the DC Hell (most of the time), but then he's also ruled parts of hell when they rolled in Trigon and the Triumvirate...it depends on the run and the writers, really.<br/><br/><strong>We'd need a GM Ruling as to how Hell actually works in this Universe, and where Trigon falls in that hierarchy</strong><br/><br/>To answer your question, though, what does Lucifer think about Trigon? He doesn't. He's heard of Trigon, he investigated his realm upon arriving in this universe (he's from a different universe, and only appeared a few months ago, hence why Batman has no data on him; he didn't<em>exist</em>in this universe until a few months ago) and he's like "Cool. Oh look, a butterfly." He views Trigon the same way as he does any of the powerful demons in his own Hell; with vague amusement, and barely disguised contempt. Half-demon offspring? Meh. He knows all about complicated relationships with father figures xD