Is DRK "crashing"? Losing 20 or even 50% after a big rally is normal in cryptoland. Normal in precious metals. Not uncommon in equities.
I wouldn't order the casket yet.
XMR vs. DRK is going to be a long, drawn-out battle.
loosing 50% in a few weeks is normal for coins with a low market cap, it's abnormal for a coin in the top 5. Most of the coins that loose that much who are in the top 5 are doomed.