  To every regular category $\mathcal{A}$ equipped with a degree function
$\delta$ one can attach a pseudo-abelian tensor category
$\mathcal{T}(\mathcal{A},\delta)$. We show that the generating objects of
$\mathcal{T}$ decompose canonically as a direct sum. In this paper we calculate
morphisms, compositions of morphisms and tensor products of the summands. As a
special case we recover the original construction of Deligne's category
$\operatorname{Rep} S_t$.
