Complex sentence: In each version the Digimon start off at Ultimate or Champion level (excluding Lunamon or Coronamon), but the tremor causes your Digimon to degenerate into the above Digimon.
Split into simpler sentences: In each version the Digimon start of at Ultimate level (excluding Lunamon or Coronamon). But the tremor causes your Digimon to degenerate into the above Digimon.