Official starter
Lee Sin, Blind Monk
How to play Lee Sin
This list goes wide. Chosen Champion is Lee Sin, Centered — buff the army, not one giant.
Many units get much better once a buff lands. Put bodies on a battlefield, spend the legend buff, then use combat spells (Challenge, Charm, Stand United) to start fights you should win.
You can be slow to assemble. Instantly ready units from those buffs let you pressure a second battlefield even from behind.
Sources: Lee Sin, Blind Monk guide — Riftbound.gg · Deckbuilding Primer