This book is also known as One Hundred Ways to Use Tentacles and A Guide to Appreciating Monster Girls.
After being reincarnated as a tentacle saintess, Lydia knows she must not let anyone discover her identity.
To protect herself, she has no choice but to use the power of her tentacles to secretly absorb energy.
Each time, she absorbs only a tiny amount of energy to avoid arousing anyone's suspicions.
She skillfully conceals her true nature, helping others as a holy saintess.
But...
A devout nun asks her with fervent enthusiasm,
"Lady Saintess, where should we go today to spread your sacred teachings?"
Her subordinates, their eyes filled with hearts, surround Saintess Lydia.
But I'm only absorbing a little energy.
Don't come any closer!
