Select waves and use Fail Rewind in Legend of Defenders

Use failure rewind for automatic fallback

1. Open the Battle screen.
2. Find Setup below End Battle.
3. Enable Auto-Battle Fail Rewind.
4. Watch what happens after a failed battle: the setting is intended to move the run back so it can continue at easier waves.

The player describes falling back five waves per loss, then progressing and falling back again as results change. Treat that number as the player's current observation, not a permanent rule for every build.

This will not pin the run to an exact farming wave

The person asking wanted to select a lower wave because the tower that strengthens enemies had become too difficult. They pointed out that repeatedly losing was frustrating and could undermine the reward benefit. That limitation remains part of the answer.

Fail Rewind reacts to a defeat. It does not provide the missing button for choosing an arbitrary wave, guarantee a stable loop, or show that a harder enemy setup earns more over the same time.

If Solar Turret is why the waves became harder

Check the Solar Turret tradeoff before chasing a particular lower wave. More reward per successful fight and more reward over a long session are different questions if the lineup spends part of that session failing.

Check the result

After a loss, confirm that the run actually falls back under the enabled setting. If the wave does not change or the interface differs, record the current Setup state and version. If it keeps moving between wins and losses, that can be the described behavior rather than proof of a hidden wave selector.