So. To get the MP for the achievement, you've got to kill every one of 5 champs.
1. only one spawns at a time,
2. the spawn is only every 40-45 minutes,
3. which one spawns is random,
4. the spawn locations are spread out, and
5. the champs melt like ice in the sun when they're attacked.
I'd just like to politely suggest that the combination of all five of the above is... ...not ideal. Especially the combination of numbers 3 and 5 - we need at least a decent chance to get to the right place in time to kill the champ.