Ishwara is in the form of Agni, at Tiruvannamalai.
Shiva-Agni is Subrahmanya.
Flaming spear, Skanda's weapon, is Shakti - Shakti Wel. It is common to worship Dewi, as enshrined in flame of an oil lamp - Bhagawati Sewa.
Wedas begin with the word 'Agni'. Wedic religion is chiefly about fire worship. Tending of sacred fire - Agni Upasana - is to be done by all classes of people.
And Subrahmanya is presiding deity for fire based rituals. In today's day to day life, idol worship is more prevalent, than tending of sacred fires.
- Shri Chandrashekarendra Saraswati, Kanchi.
