In the Mahabharat He is referred to as Marutatmaja. The word Maruti has originated from the word Marut.
There are many schools of thought regarding Maruti and Rudra.
Maruts are the sons of Rudra and so is Maruti.’
‘There are eleven rudras. Since Hanuman too is a rudra He is included
in these eleven. Bhim is one of the Names of the eleven rudras.
Hanuman has also been referred to as “Bhimrupi Maharudra”. It is
believed that probably Hanumant’s five faced idols have been derived
due to the influence of the five-faced idol of Rudrashiva.
Hanuman is considered an incarnation of Lord Rudra. Researchers opine
that the relationship between Hanuman and Rudra must have originated
in the era of the Purans. In the story from the Ramayan narrating
Hanuman’s birth, Vayu (generated from absolute air) is referred to as
His father. Later due to His innate qualities He became an incarnation
of Lord Rudra. The relationship between Hanuman and Lord Rudra has
been clearly illustrated in the Skand Puran, Brahmavaivarta Puran,
Narad Puran, Shiva Puran, Bhavishya Puran, Mahabharat Puran, etc.’