It was introduced with other "ocular O"s which are seemingly more commonly used than this one.

It's not quite an illuminated initial.

"This document requests the addition of a number of Cyrillic characters to be added to the UCS. It also requests clarification in the Unicode Standard of four existing characters. This is a large proposal. While all of the characters are either Cyrillic characters (plus a couple which are used with the Cyrillic script), they are used by different communities. Some are used for non-Slavic minority languages and others are used for early Slavic philology and linguistics, while others are used in more recent ecclesiastical contexts. We considered the possibility of dividing the proposal into several proposals, but since this proposal involves changes to glyphs in the main Cyrillic block, adds a character to the main Cyrillic block, adds 16 characters to the Cyrillic Supplement block, adds 10 characters to the new Cyrillic Extended-A block currently under ballot, creates two entirely new Cyrillic blocks with 55 and 26 characters respectively, as well as adding two characters to the Supplementary Punctuation block, it seemed best for reviewers to keep everything together in one document.

(...)

MONOCULAR O Ꙩꙩ, BINOCULAR O Ꙫꙫ, DOUBLE MONOCULAR O Ꙭꙭ, and MULTIOCULAR O ꙮ are used in words which are based on the root for ‘eye’. The first is used when the wordform is singular, as ꙩкꙩ; the second and third are used in the root for ‘eye’ when the wordform is dual, as ꙫчи, ꙭчи; and the last in the epithet ‘many-eyed’ as in серафими многоꙮчитїй ‘many-eyed seraphim’. It has no upper-case form. See Figures 34, 41, 42, 55."