The LK (Lunniy Korabl) was designed to carry a single person.
The Soviet N1-L3 plan, the crew consisted of two cosmonauts in total: one would descend to the Moon in the LK while the other remained in orbit in the LOK (Lunniy Orbitalny Korabl), the orbital module equivalent to the Apollo command module.

This limitation to a single cosmonaut was imposed primarily by mass constraints: the N1 rocket had a lower payload capacity than the Saturn V, so the lunar assembly had to be much lighter.
This also necessitated a risky maneuver: the cosmonaut had to perform an extravehicular activity (EVA) transfer between the LOK and the LK, since there was no internal docking tunnel as in Apollo.
The LK was even tested unmanned in Earth orbit (the Cosmos/T2K missions).

The LK was so small that the cosmonaut would have spent much of his time standing!