Abstract: Concepts from quantum information theory have become increasingly important in our understanding of entanglement in QFTs. One prominent example of this is the entanglement (or modular) Hamiltonian. Using complex analysis, we determine this operator for the chiral fermion at finite temperature on the circle - which is not fixed by conformal symmetry - and show that it exhibits surprising new features. This simple system illustrates how a modular flow can transition from complete locality to complete non-locality as a function of temperature, thus bridging the gap between previously known limits. We derive the first exact results for the entanglement for the different spin sectors on the torus.