As the name might imply, vluks uses Hashicorp Vault in Transit mode to authorize decryption of LUKS version 2 disks.
It can be embedded into the first stage of the Linux boot process, to facilitate unlocking of LUKS volumes by providing keyfiles to systemd-cryptsetup. Keyfiles which are stored in the LUKS header itself, encrypted with Vault's transit secrets engine, enabling conditional access to volumes depending on the client's Vault privileges.
In future, vluks can also be run as a daemon on the resulting host, to shut down machines if it detects the Vault has become sealed or unreachable for an extended period of time.