Beta is a Warrior hero, with the following Leader trait:

One with the Herd

Beta is not attacked by walkers when he moves past them. Passing by a walker gives Beta X% chance to gain up to 1 Charge Point; each passed walker increases this chance by Y%. Every walker passed by Beta becomes a part of the Herd, following Beta and not attacking him nor his allies during the next turn. Tank, Spiked, and Goo walkers cannot become a part of the Herd. Attacking a herded walker removes the status (incl. Overwatch attacks)

As a leader, each member of your team gains this trait.

Notes:
•  If your survivor who herded walkers gets into struggle, the status effect is removed
•  Passing by a walker in the case of Beta's leader trait follows the same rules as Huntsman's Daryl Prowl (in other words, if the walker would be attacked by Huntsman Daryl, then with the effect of One With The Herd leader trait the walker gets added to the Herd)
•  Beta's Leader Trait and Huntsman Daryl's Prowl interaction: if Beta is a team leader and Huntsman Daryl is in the team, Prowl overrides the effect of One With The Herd on the first passed walker (as the first passed by walker gets attacked by Daryl in this case; attacking a walker cancels the Herded effect), but the subsequent walkers passed by Daryl during the same move will be added to the Herd. If Huntsman Daryl is a team leader, it works the same way for Beta in the team - the first walker will be attacked by Beta and not herded, and subsequent walkers passed by Beta during the same move added to the Herd
•  The Herded effect lasts one turn; walkers can be herded again on the next turn by passing by them
•  There is no limit to how many walkers can be herded in one turn (i.e. limited only by how far your character can move)