I is for Immortal  Immortal means Eternal.  All souls are
immortal. But, while karmas* are still attached to the souls,
the souls occupy into various types of bodies, like the humans,
the animals, the birds, the plants, etc. The body and the soul
are different things. When all the attached karmas are destroyed
the soul is liberated from the body permanently and reaches to
the top of universe, called Siddh Shila and stays there forever.
These souls then are called Siddhas. That is the state of being
our Immortal soul from the bondage of the body.  * look under K