Hayato is hot-tempered and tends to be irritable towards anyone who isn't Tsuna, Reborn, and Nana, with the biggest nuisance towards him are his own fellow guardians. He cultivates the image of a "bad boy" by smoking heavily, having a hostile attitude, dressing like a delinquent, and even attempting to harm others if not for the intrusions Tsuna and Takeshi, who restrain him. Despite his image as a school delinquent, Hayato is shown to be quite intelligent and finds many of the tests and schoolwork to be easy, unlike his boss.

Hayato takes his duties towards acting as the right-hand man of Tsuna very seriously, to the point where he strongly dislikes whenever others interact with Tsuna in any way, especially towards Takeshi, who he considers a one-sided rival.

In contrast to the more impulsive Takeshi, Hayato has a very methodical and calculated approach to battles, it is commonly assumed that he had a multitude of private tutors when he was young, as he was brought up in a rich househould. 

Voice Range: Med-Low, to Med.

Voice type: rich with tone, peaceful, obssesive, loyal-ish

Here's some reference:

(Ignore the teen with the blue hair, I'm looking for a voice like the red haired guy has):

https://youtu.be/bljq4q_JUhU?t=2m33s