Quests:Dun Barethsol:Agdan's Revenge

When Marcella meets Agdan in the cemetary, Agdan may hint at having revenge on Reylyr by killing her husband, Konas Kon. Murdering Konas would shift Marcella's alignment toward evil, making it easier for her to deal with the criminals and the Enders and harder to deal with everyone else. Corin dunThalen would also know about the crime, as Agdan is kind of haunting his resting place as well as the cemetery above it.

Alternatively, Agdan could suggest Marcella blackmail Konas with the threat of revealing his crimes to Jelom and Talan. Soko, Reylyr, and Konas care very much about avoiding notice, so any threat to reveal their crimes could either buy the player new knowledge and the respect of the thieves (if she's evil aggressive enough to pull it off) or get her killed. That works too. This path would shift her toward evil, but not irreversibly.

Finally, Marcella could kill Konas, avoid capture, and then blackmail Reylyr. This, however, is the most risky path, with the payoff being more experience and an alignment shift all the way to -5. Reylyr and Konas are both evil and more powerful than Marcella, at least at the beginning of the game. Either of them could kill Marcella. Reylyr, once she realizes that Marcella is the killer, would have to be managed very carefully indeed if Marcella wants to be taught and not killed.