Ayyappan is a popular south Indian deity who is worshipped with outmost dedication and devotion. Sabarimala is considered as the abode of Ayyappan.
He is said to be born from the union of Shiva and Vishnu(At that time Vishnu was in the disguise of a beautiful woman-Mohini) That is how he acquired the name Hariharaputra.
The Lord is considered as the exterminator of sorrows and he the giver of peace and prosperity. An idol of Ayyappan is worth keeping in your Pooja Room.