Who does katniss struggle with at first and who kills him?

At first, Katniss struggles with Peeta Mellark in the Hunger Games. She initially sees him as a weak and useless competitor, and their rivalry is mostly about survival rather than outright malice.

However, Peeta is not killed in the Games. He survives, and the two develop a complex relationship throughout the series.

There is a lot of speculation about their relationship and whether or not it is genuine, but in the end, they come to rely on each other for support and protection.