The Princess's Guard: A Century of Cultivation from the Start Every Day

(The rating just came in) After transmigrating into a guard for an abandoned daughter of a prince's household, Su Mu awakens the "Help in Times of Need" System. From the start, he obtains an astonishing cultivation technique. His cultivation increases by a hundred years each day, and he can absorb other people's cultivation as well. When the commandery princess is ambushed, he turns around and drains the assassins' cultivation. While others toil through their cultivation, he lounges around and gains a hundred years of power each day, along with a long-lost sword art, an unparalleled movement technique, a body immune to all poisons... The princes see him as a pawn worth recruiting, the princess consort regards him as a thorn in her side that must be removed, and the immortal sects watch him with quiet suspicion. Su Mu merely rubs his lower back and smiles at the peerlessly beautiful commandery princess, who has grown increasingly dependent on him: "Don't be afraid. There's plenty of charcoal." "Anyone who lays a hand on you, I'll burn to ashes."