Those That Live By The Wands Shall Die By My Blades.

What kind of situation is this when am should buy difusal blade?

your manavoid explanation telling people to use percentage is wrong. It's based on how much mana is missing.
For example, BS with 40/400 mana has 10% mana, Lina with 280/1000 mana has 28% mana. If you follow your guide and ManaVoid lowest mana percentage you'd hit BS since 10% < 28%. But BS only missing 360 mana. Lina missing 720 mana. Damage from casting on Lina is double damage from casting on BS

I enjoyed this overall but in the item build maybe make it more clear that Yasha will build into Manta Style (btw yes i did upvote as this is good for the beginners and medicore players) :D