Current questions and answers regarding the map editor.

User01322342, I described this in the FAQ from my signature. Quests have the ability to customize stages:

ProgressCommentsFileRef – if the quest consists of several stages
(for example, kill 3 groups of monsters), then you can add files with
additional descriptions for each stage. In the game, the general
description of the quest from DescriptionFileRef will be displayed first, and then the description of the current stage from
ProgressCommentsFileRef. If the quest has stages, it will be at
stage zero at the start.

-- quest progress
-- progress – the stage number corresponding to ProgressCommentsFileRef
SetObjectiveProgress(‘SCRIPT_NAME_OF_THE_QUEST’, progress);

You can check for monster kills using a trigger at the end of the battle. The quest should, of course, be custom.