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The nucleus of the active galaxy NGC 5548 was the target of two intensivespectroscopic monitoring campaigns at X-ray, ultraviolet (UV), and opticalfrequencies in 2013/14. These campaigns detected the presence of a massiveobscuration event. In 2016/17, Landt et al. conducted a near-IR spectroscopicmonitoring campaign on NGC 5548 and discovered He i 1.08 {\mu}m absorption.Here we decompose this absorption into its components and study its timevariability. We attribute the narrow He i absorption lines to the warm absorberand, as for the newly appeared low-ionization warm absorber lines in the UV,their presence is most likely due to a reduction in ionization parameter causedby the obscurer. The observed variability of the narrow He i absorption isconsistent with what is expected for the warm absorber. Most importantly, wealso detect fast, broad He i absorption, which we attribute to the obscurer.This He i broad absorption, which is indicative of a high-column density gas,is unsaturated and variable on time-scales of a few months. The observedvariability of the obscurer is mainly due to changes in ionization, althoughdensity changes also play a role. We test the physical cycle model ofDehghanian et al. which proposes that helium recombination can account for howthe obscurer influences the physics of the warm absorber gas. Our resultssupport their model, but also indicate that the reality might be more complex.

Broad He I 1.08 {\mu}m absorption from the obscurer in the active galaxy NGC 5548