Lilith Sahl in the light novels may be even more sadistic than Dietrich. She gave Abel a chance to save himself because she believed in him blindly... at a time when he was a murderous sociopath who killed millions.
Abel, and certainly megalomaniac Seth may be interpreted as other than 100% benevolent, especially considering their bloody past.
Common Knowledge: Contrary to popular belief, Kentaro Yasui didn't actually finish the series nor helped in completing the manga. He did, however, write a short story called Trinity Blood Apocrypha featuring Astharoshe. And the manga ended the same way as the novels
Ho Yay: Tons of it. Abel seems to have a thing for Tres, especially in the manga. Also Radu and Ion. And Radu and Dietrich (Radu couldn't shut up about how beautiful Dietrich was while he was being tortured). And Esther Blanchett and Shahrazad al-Rahman's very special friendship in both the novels and the manga adaptation. And Jane and Mary in the novels. And Jane with Esther and Mary with Paula in the novels.
Lampshaded in the manga, when Esther asks Abel if she's "in the way" while she's travelling with him and Tres to Rome, and Abel's reaction is "Tres and I aren't like that! This isn't a yaoi book!"
Tear Jerker: Lots and lots of them: Gyula's death in Esther's arms, Ion's last farewell to Radu, Shahrazad's death in Esther's arms, Alessandro's death in Esther's arms, Esther at Abel's tomb...)
by BUCK-TICK really brings the gothic feel in the show.