Final answer:
Nazrul became the main poet of the leto group upon joining, composing various folk plays and securing his significant role within the group.
Step-by-step explanation:
When Nazrul joined the leto group, he did not remain on the fringes or have a limited role; instead, he became the main poet of the group. Nazrul made his mark within the group by composing a number of folk plays and thus establishing his place there. Through his contributions, Nazrul became a prominent figure, allowing the group to further their expression through his poetic talents. This allowed him to showcase his talent and creativity within the group. It was not mentioned that he was sidelined or had a limited role. Nor was it mentioned that he distanced himself from the group or left due to creative differences.