
And on a side note, the best defense against magic damage: 
Then
and
and
and
and 
The idea is you want to negate as much damage in a uncounterplayable wag as possible. Health can be shred with % health damage. Armor and mr can be penetrated, but % damage reduction passives like those on randuin’s, ninja tabi, and adaptive helm can only be dealt with via true damage, which can be countered by shields and invulnerabilities which do not increase damage taken from % health damage and do not get penetrated by penetration items. I put gargoyles stoneplat roughly into this category because while doubling max hp does increase % health damage, it also boosts the shields on two of the prior items, boosts nautilus’s w shield, and synergizes with alistar to make him effectively take no damage for an item that is fairly cheap. It effectively halves the damage take by anything that isn’t % health damage too, so regardless of anything that true damage hit will only be dealing half as much as normal. For champs that build sufficient ad or have significant amounts of single target with some ad scalings,
effectively funtions as a % damage reduction item.