A complete OWL2 DL reasoner focused on correct inference and on exposing logical modeling errors in expressive axioms. It is well suited for deep consistency checking and classification of medium-sized ontologies where correctness matters more than raw speed. Compared with ELK it is usually slower, but provides full OWL2 DL semantics. In enterprise settings it is often used as a “gold standard” QA step; SHACL/SPIN validation is separate.