Now, after the events of “Goldfaced” and considering how Season 5 has progressed, I’d say that the time has come for The Flash to start killing characters off.
The Flash has never been the darkest or most deadly show in the Arrow-verse, but it does manage to serve up a seriously scary supervillain every year.
Nevertheless, Team Flash has mostly been able to stick to its no-killing stance, and Barry has fought to keep himself on the straight and narrow without taking any lives at various points over the years.