WARNING: This is kind of long.
As overlord I'm doing the Ascention quest. For those of you who know what this quest is, feel free to skip ahead to the next paragraph. The Ascention plot revolves around destroying cities. I can spend 0 XP to buy a plot card that places a "Temple" on a destroyed city. Once there are four Temples in play, I can play a 20 XP plot card that does the following (paraphrased): "At the beginning of your turn, put a comet token on a Temple. All heroes have their maximum health and fatigue reduced by one for each comet token within 3 trails of their location. Once there are seven comet tokens in play, the overlord wins. The heroes can enter the keep at any time."
So, we are exactly halfway through Silver at 300 conquest. I have 62 XP and have destroyed 3 cities. The final city will be rolled to destroy in two weeks, and the heroes won't be able to get to it in time. So basically, very soon I will have destroyed all the cities I need. I have not purchased any Temples yet, so in a minimum of 5 weeks I could be placing comet tokens. Here is the question: do I want to gain significant amounts of XP anymore?
The more XP I gain the faster we get to gold level. Ideally we will just enter gold level before the heroes enter the keep, so I can purchase Diamond monsters while the heroes have as few gold items as possible. I already have 62 XP and I will gain 5 per turn when the final city is destroyed. What incentive do I have to kill the heroes a lot? I will only be ensuring gold level arrives sooner, and with it the overpowered items (and another fatigue upgrade and the gold level relic, if they have time). The further we are into gold when they enter the keep the less chance I have of victory. Of course, once the keep starts I will want to get as many kills as possible so my avatar's health goes up.
It seems to me the best plan is to get event treachery maxed and destroy their items as much as possible. Am I wrong in thinking this? I'm hoping so, as it's very unfortunate that the best plan is to actually not kill the heroes at all (or maybe only 10 XP worth per 3 dungeon levels). It would be boring for them and me. I don't think I will go that route even if it is the best strategy, but it will be annoying to think that by playing hard and killing them I'm actually hurting myself.
Thoughts? Did I miss something? I hope so.