was observed in raster mode with a moderate cadence of 45 s, so that a full study of the temporal evolution of the chromospheric condensation could not be carried out. In the present paper we expand on these findings, using the unique dataset of Paper I to study the full temporal evolution of multiple chromospheric lines, in multiple flaring kernels, during the impulsive phase of the flare, with excellent spectral and temporal resolution. Following @2017ApJ...836...12K, we take advantage of co-temporary HXR data from Fermi [@2009ApJ...702..791M], as well as the IRIS Slitjaw Images (SJIs) to properly estimate the full parameters of the energy input. We further synthesize the Fe [ii]{} 2814Å  line for comparison with the data; as shown by @2014ApJ...794L..23H [@2017ApJ...836...12K], this line is an important diagnostic in flares because the intensity originates from a similar temperature range (with a broad peak around $T\sim12,000$ K) as hydrogen Balmer bound-free radiation that dominates the IRIS NUV range.

The SOL2014-09-10T17:45, X1.6 event {#sec:flare_description}
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The GOES X1.6 class flare SOL2014-09-10T17:45 developed in active region NOAA 12158 near disk center (N15E02). The complex two-ribbon structure encompassed both the western portion of the main, leading polarity sunspot, and a group of several smaller spots 