Descent is balanced towards the heroes, if certain conditions are met:
- Played with 4 Heroes, regardless of actual player count
- Descent scales terribly. The actions of all 4 heroes are necessary to counter the spawn rate of the overlord and all 4 pair of eyes are necessary to see enough of the dungeon to restrict spawning locations.
- A balanced quest is selected
- Quest 1 in Descent Base Game is balanced in favor of the heroes, as it introduces people to the game, while other quests are clearly very challenging for the heroes
- All rules are followed
- Descent has a couple of quirky rules and especially new players struggle with them. Make sure all rules are played properly, especially regarding combat, spawning and movement.
- Use skills to the best of your abilities and combine skills of multiple heroes for great synergies.
- Skills (hero skills as well as skills gained from cards) provide awesome abilities, which really make your life easier. Guard fragile heroes with your defensive characters (shields are a must!) and use your fragile offensive heroes with a lot of endurance to cleanse the rooms as quickly and efficiently (in terms of actions) as possible.
Additionally my impression is, that descent 1st edition benefits from the expansions, which further equals the playing field. While most quests in well of darkness or altair of despair are clearly in favor of the overlord, the feat cards from tomb of ice help in critical situations, which gives heroes a needed boost in those few critical moments.
Last but not least:
The heroes should be aware of the "runner". Fast heroes (5 movement) with high endurance (4-5) can move up to 17-19 spaces (run action (10 movement) with a endurance potion (4 endurance for movement, 1 to drink potion, again 5 endurance for movement). Frequently this means: Open a door with the 1st turn of the 1st hero and then let the runner open the unguarded chest and disappear through the glyph. This provides items for the party and 3 quest markers, to heavily boost the situation of the heroes (heroes can now die again, due more markers and are harder to kill due to better equipment).
If after all these changes, you still consider that you need a handicap, then I would consider the "official play-tested handicap" from the road to legend expansion. The Spawn Marker. Rules:
- The overlord can only spawn if the spawn marker is on it's active side.
- If the overlord spawns, the marker is turned to its inactive side.
- The marker is activated when 1 of 2 things happen:
- The overlord pays 15 threat
- The overlord reveals a new area of the map.
You can simply print your own double sided spawn marker or write it down on a piece of paper. This handicap restricts the most powerful option of the overlord, while it does not completely destroys the overlord. He can spawn freely once per area and if the heroes took to long (i.e. threat piled up), but he can't "spam" the map with monster, which is most often the problem of the heroes.
I've played with this option in vanilla descent and with all 3 expansions thrown in and it worked very elegantly in all scenarios. The games are balanced and the overlord still has all options available to him. The games actually benefited from it, as more attention was paid to other interesting options of the overlord, like traps and spells. This provides more "flavor" that the overlord, instead of only being "lord of the monsters" he now feels truly evil.