Good mix just to get out of the way
Some people are always questioning my LAST WHISPER as first item builds and when they try it, it just flat out sucks and they die. Well let me explain how last whisper first works and how items in general work, and I am writing this to kinda cement it into my own brains ans I often get carried away and do the same mistake! : -------------
Tank stats are SUPER STRONG in full ALL IN, their weakness is if a person is walking away from you, you won't kill them / there's LESS CHANCE of killing them
What last whisper gives you is not all in power against armored / healthy champs, I mean it does more or less,, but not straight up. See it gives you power to actually have effective harass and effective damage against armored target, but the effective health / damage from sheer base damages and abilities they have is TOO HIGH at 1 item point. There's no way you will kill a sunfire 1st DPS champ with Last whisper first if you both just stand and duke it out, you will though if you have either some minor resistance yourself like a chainvest to absolutely nulify their base damages into the ground OR having range advantage. Like lets say Darius has his Q, even if they build armor you can pop few Q's on them and they have nothing anymore, they are done. + Darius naturally has crazy burst for early game, so even if people buy armor and health it wont be enough, their natural DPS can barely match it no matter how much defence they buy. I even bursted 4k HP udyrs in 2 seconds with Darius, its no joke! ( thats with infinity edge though ROFL )
Anyway TL; DR being = Last whisper gives you kill potential, but it leaves you open to death aswell. Don't underestimate base damages early game ( pre 3 items ) You have <1000 HP early game and most spells do over 150 pretty much starting rank 2. Be careful, if you die to tank and lose lane, you can't farm anymore and lose game for your team RIGHT AWAY BY YOURSELF.
One of the good combos for lets say beating a nasus is Last whisper + thornmail combo. Get chainvest inbetween last whisper if he isn't building defense ,but went for sheen or so. Nasus early all in is no joke with maxed spirit fire.