In Patch 4.4 Kassadin's kit has been reworked, meaning he is much less of an unkillable high-damage mage in the late game and is more focused on his mobility. His defining skill - Riftwalk - has been changed so that it does heavily reduced damage (based on mana rather than AP), although at level 16 it has an incredibly low 3 second cooldown. Add 40% cooldown reduction items and you have a mini teleport every 1.8 seconds! Outrunning a Kassadin (who has plenty of mana) is now even more impossible than before, especially when combined with his E slow and items such as Blade of the Ruined King and Iceborn Gauntlet. AD/Tank Kassadin is essentially an inescapable DPS monster.

Kassadin is known to dominate thanks to his exceptional ultimate ability. Since his Patch 4.4 rework, this ability's damage now scales based on his total mana rather than AP. Put simply, this means that AD Kassadin is not only an alternative, but in my opinion much stronger that an AP-focused build. A combination of defence, physical damage and a lot of mana items create a champion that is an extremely powerful chaser and bruiser, while still dealing as much magic damage with his infamous ultimate ability as he would if built AP. Building Kassadin with a focus on AD, mana and tankiness allows him to clear the jungle effectively, though certainly not spectacularly. His level 6 ganks, however, are unsurprisingly deadly. Since his rework his silence/burst combo is gone, making melee DPS and high chase a great alternative.

Pros

• His ultimate is essentially a damaging flash every 1.8 seconds at max rank with 40% cdr.
• Doesn't miss out on too much in terms of ability scaling by building him AD rather than AP.
• Practically inescapable in chases.
• Has tonnes of map pressure, particularly when taking Teleport.

Cons

• Unexceptional jungle clear speed.
• Ineffective ganks before hitting level 6.
• Item reliant when built AD/Tanky, suffers without heavily farming the jungle or successful ganks.

Jungling Tips

• Start with a point in Q to shield yourself for the first jungle camp.
• Don't attempt to counter jungle before level 6 as your clears aren't fast enough and you have no escape/kill potential.
• Farm to level 6 as fast as possible, avoid early ganking and only hold lanes if absolutely necessary.
• W + Smite is your best AD damage spike for securing objectives (dragon/baron), particularly with spellblade from Iceborn Gauntlet/Triforce.

Ganking Tips

• Don't attempt to gank pre-6 unless the enemy is heavily overextended/low on health and you are guaranteed to pick up a kill. You won't fare well if they bait and counter-gank.
• Use wards & teleport to gank from unexpected locations.
• After one or more towers are down, focus on ganking long, open lanes. You have awesome chase and DPS but lack high burst damage/cc.
• For the same reasons as the above point, only gank short lanes such as mid when the enemy is low on health and your laner has high burst damage or heavy cc.