Missing children...

[sticky-runes]

One of the kids was cut down by a bandit during this battle and when I handed in my report at the quest guild, it came up as failed. I still got to recruit Karl, but will the quest appear again?

[Antimatzist]

I don't think so.

[sticky-runes]

the quest doesn't seem to be reappearing. Oh well. The people of Merseto should look after their kids better.

[gildedtalon]

I once missed talking to Karl with Kyril and the quest never reappeared

[Wolkendrache]

Either the game is wrong or Lalacle tries to double-deal you. Here is the quest description:
"Some children went to play in the ruins of Collanbal and never returned. We fear the monsters may have gotten them. We'd like you to go find out what happened to them."

So if you return and say "I found it out: they were slaughtered, and this baldhead is my witness", then you fully deserve your reward because you've 100% done what you were asked for. Tsss...