  Quantum spin liquids are exotic states of matter which form when strongly
frustrated magnetic interactions induce a highly entangled quantum paramagnet
far below the energy scale of the magnetic interactions. Three-dimensional
cases are especially challenging due to the significant reduction of the
influence of quantum fluctuations. Here, we report the magnetic
characterization of {\kni} forming a three dimensional network of Ni$^{2+}$
spins. Using density functional theory calculations we show that this network
consists of two interconnected spin-1 trillium lattices. In the absence of a
magnetic field, magnetization, specific heat, neutron scattering and muon spin
relaxation experiments demonstrate a highly correlated and dynamic state,
coexisting with a peculiar, very small static component exhibiting a strongly
renormalized moment. A magnetic field $B \gtrsim 4$ T diminishes the ordered
component and drives the system in a pure quantum spin liquid state. This shows
that a system of interconnected $S=1$ trillium lattices exhibit a significantly
elevated level of geometrical frustration.
