Maybe I've just played too much Shadowrun (the old Genesis version) but I feel like "escort" style missions would be a relatively simple but compelling addition to DotE. This is essentially a random encounter with some hapless character (think: the little girl from Alien) who gives you something nice if you can bring them safely to the exit with you.



This character would:

• Consume a Hero slot;
• Be moveable like a hero (e.g. you can choose which room to move them to);
• Not attack anything (only requires idle/walk/death poses);
• Not equip anything (no equipment slots of any kind);
• Have no active skills;
• Sometimes have a positive passive skill (e.g. +10% Dust drop chance, Repair ability, can operate major nodes, etc.);
• Sometimes have a *negative* passive skill (e.g. -10% defense to all heroes in the same room);
  
  

Giving up a Hero slot could be a huge risk, so the rewards for a successful escort should be substantial, for example:

• Rare weapons/armor/items;
• Big industry/science/food drops (e.g. +200 industry);
• A blueprint (e.g. automatic unlock of a random node on the tech tree);
• Automatic level-up for a random character in your party;
• Automatic level-up for ALL characters in your party;
• A map for the next level of the dungeon (e.g. you start the next level with a sillouette of all rooms revealed);
• A compass for the next level of the dungeon (e.g. you see a beacon showing you where the exit is);
• A witty one-liner
  
  

Choosing to abandon a hero late in the game to make room for an escort for a potentially massive reward is a nice risk/reward proposition

And a variant on this idea:



Rather than giving up a Hero slot, the Hero in your party who interacts with the escort character (e.g. the hero you have selected when you "accept the mission") gets saddled with the escort character until one of them dies or until you reach the exit. The escort character would just follow the hero everywhere. Abandoning the hero would also abandon the escort.



Another variant:



Some random escort encounters are not optional, e.g. the escort immediately attaches to the hero who opens the door to the room. This would act like a temporary "curse" on that hero, with the only remedy being to abandon the hero, get the escort killed by monsters, or reach the exit.