The present work investigates the reconstruction of the quantum layer of the effective description in a timeless Euclidean model on E⁴ with a single fundamental real field Φ satisfying the Laplace equation.Using a working region Ω, an observer body Ω₀ ⊂ Ω, and a foliation-based description of local readouts, we formulate an operational reconstruction scheme for states, observables, and causally consistent dynamics in operationally accessible regions where an effective description in terms of foliations and effective fields remains valid. Within such regions, the previous GR reconstruction singles out the locally inertial SR regime as the working form of effective analysis. We then consider a working class of states consistent with transfer locality, the reflection structure with respect to the foliation parameter, thespectral condition, and stable registration.In this regime, the standard OS/GNS reconstruction yields a Hilbert spaceof states, a self-adjoint Hamiltonian H ≥ 0, and a strongly continuous unitary evolution.At the same working level, a compatible positive complex structure is fixed on the space of initial data, after which the one-particle space, the Schrödinger equation, the Born rule, the POVM description of measurements,and the local continuity equation for the probability current are constructed. It is further shown that, for free effective sectors, transfer locality, the constraint on the principal symbol, and consistency with the previously reconstructed observable SR structure lead to the standard first- and second-order relativistic closures. Thus, what emerges within the model is not a full interacting local quantum field theory in all its physical completeness, but rather the quantum coreof the effective description together with its relativistic closure in operationally accessible regions where the locally inertial SR regimeremains valid. As established in the preceding GR reconstruction, strong-field regimes ofgravity and effective fields are excluded in such regions; their occurrence is possible only in operationally inaccessible regions, where effective reconstruction in terms of foliations and effective fields must give way tothe fundamental description in terms of the field Φ. A substantial structural consequence is the classical status of the gravitational sector: quantization applies to effective nongravitational fields, whereas gravity does not generate an independent local spin-2quantum sector. The obtained result continues the program of reconstructing effectivephysics from a timeless Euclidean model, within which observable SR kinematics and the geometric GR sector were reconstructed previously.