The Champ has two phases. In the first phase, he attacks and gains Strength. When his HP drops below 50%, he enters his second phase, gaining a large amount of Block and preparing a powerful 'Execute' attack. The key is to burst him down from 50% HP to 0 as quickly as possible, or to have enough block to survive the Execute. Applying Weak is crucial in both phases to reduce his damage output. Don't let him scale too much Strength.
