Who is the greatest god
In Jainism, there is no concept of a creator god or a single "greatest god" as in some other religions. Instead, Jainism teaches that every soul (jiva) has the potential to achieve the highest state of spiritual perfection, known as kevala jnana (omniscience).
The beings most revered in Jainism are the Tirthankaras. Tirthankaras are enlightened souls who have conquered inner passions and have shown the path to liberation (moksha). There are 24 Tirthankaras in this time cycle, with Lord Mahavira being the most recent.
Jains bow to the qualities of perfection, knowledge, and liberation embodied by the Tirthankaras, not to a creator god. The prayer "Namokar Mantra" is an expression of reverence to these liberated souls, Arihants, Siddhas, Acharyas, Upadhyayas, and Sadhus, acknowledging their spiritual achievements rather than worshipping them as gods in the theistic sense.