This article addresses the design of activity generators in the context of serious games for declarative knowledge training. Designing these generators is a complex task requiring specific knowledge and guidance, which falls under the scope of research in engineering. Our proposal is a design and implementation framework for generators of training game activities. The framework is a model and metamodel oriented software infrastructure that must be extended for domain specific facts. The resulting generators provide adapted and varied training activities in the form of dungeon levels for Roguelite-oriented games.