I like this piece a lot. The title sets it to be ominous and you present a shadowy character in this poem, you don't offer any description of them, as fireflies surround them, making them a silhouette, they offer you blood-stained roses; purple ones at that, indicating that this was love at first sight, or was supposed to be that since their blood is on it, it indicates they've been through hardships in their quest to court/love you. What you do offer is key - you say the river is ominous, and that means you don't trust that person fully which relates back to the title. As short as this piece is, you've put a lot of effort into it, and I genuinely enjoyed reading this :)