In Mass Effect 3, Shepard can accept a mission to assist a missing Krogan team. The team went missing while investigating Rachni activity on Utukku. This mission will vary depending on your decision to free or kill the Rachni Queen in the first Mass Effect game. The mission will take
you through dark tunnels with dead Krograns. Some of Mass Effect's more horrific enemies, such as the Ravagers, Husks, and Cannibals will attack you by surprise.
Horrific dark caves and fighting off masses of Husks might not frighten you, but realizing that this mission could lead to Grunt's death is sure to make you uneasy. Letting the Rachni Queen live may make you temporarily feel better, but it leads to Krogan casualties. Make sure to complete Grunt's loyalty mission in Mass Effect 2, or else these caverns will also be his final resting place. You'll also receive an email from Urdnot Wreav, blaming the massive Krogan casualties on you.