Chinese Scientists Reveal Experiments with Virus 100% Fatal to Mice

If you don't trust NTD's reporting, you can always refer to the source preprint

Isn't a virus which kills it's host a failure?

Not much f it can infect more than 1 other member of the host population first.

See Ebola or Marberg viruses.

Neither Ebola nor Marburg kill its main hosts in fact

Rabies then.

This should end well.