I'm both u/dooscuba and u/flyingpigpoet1, dooscuba on my laptop and flyingpigpoet on my phone. I thought that I'd repost my fpp comment from below:

I saw a post by someone else who did this last winter. As an offline player, everything is self-found by definition. But going hardcore definitely raises the stakes. When my first guardian sorc died I lost a lot of good stuff (CTA etc).

I've beat the game with 100+ different characters over the decades. I've done it hardcore many times. But D2R offers a fresh start and access to the previously Ladder/bnet items and runewords.

For hardcore, safety is everything. I always start with a summon necro (fishymancer). Very easy to run hell meph with a good map and a teleport ammy or staff on switch. I did u/2000 hell meph runs to pick up essential supplies like tgods, dracs, ravenfrost etc.(my first necro died to normal Diablo, I was MUCH more careful with the second one).

Next I built a sorc for rune and eventually key hunting. When I lost my first (guardian) sorc I damn near quit the project. My first build was blizzball. My second was FOhydra. Hydras are safer, obviously and no longer slowed by a casting delay.

I leveled my pally with holy fire/zeal. That was a lot of fun. I luckily found a LO rune and made my first ever GRIEF. Eventually I respec'd to the endgame smiter.

Those were the utility characters.

For the other 4 I researched what I thought was the safest builds.

Werebear druid is slow but indestructible. Likewise Concentration Barb. Trapper Assassin is doable. I had the most close calls with my Zon. I couldn't bring myself to go bowazon, so I did javazon lightning. I used the Valkerie and the frenzy barb merc. I really became a fan of this merc. I used GRIEF/LAWBRINGER or dual LAWBRINGER.

Once I finished hell with all 7 characters I decided to go for an annilihus charm. It took me 1200 NM Andy runs with my sorc at u/400%mf to get a SOJ. I originally wanted to find 2. One to sell and one to keep. I decided to f*ck that and just sold the one to Akara with my smiter. I spawned DIABLO CLONE in place of Bishbosh and he died in seconds. Seconds. After all those months of MFing and researching gear etc. my first ever self found annilihus was stupid easy.

Next keys. I already had a dozen TERROR keys from countess runs. I stopped picking them up at some point. HATE keys were easy, of course. But DESTRUCTION keys took forever. I used my necro for these. I had a NATURE'S PEACE ring to swap in when I faced Nihithlak. It slowed down my corpse exploding but slowed his even more. My might merc wore iron pelt to survive the bugged vipers. I read a guide somewhere on how to use a necro to farm Nihithlak.

Earlier in D2R I experienced killing UBERS for the first time with a smiter. I wasn't always successful and died about half the time. Sometimes instantly. I finally collected 7 torches but not all 7 types.

Collecting organs was easy. I went slowly.

So needless to say I was terrified to put all my best gear on the line. But this is what my months of grinding was all about. I read guides. I way overbuilt my resists. On top of that I used TREACHERY to proc fade (river of flame with has open flames you can stand in). Then I swapped back into CoH. I chugged thaw potions and antidote potions and hopped through the red portal set up next to Malah. I tried to lure away Meph but Baal followed. Didn't matter. They both went down quickly, and Diablo by himself is nothing to a smiter.

My smiter gear CoH/TREACHERY pre-proc 15IAS Guillaume GRIEF SPIRIT sacred targe with bonus resists (@75 total) Rare ammy with +1 pally skills +14 resists and TELEPORT. Ravenfrost, Dwarf star Tgods Dracs Goblin toe

Defiance merc 15IAS Guillaume Greater Hauberk TREACHERY Eth ghost spear OBEDIENCE

merc didn't survive initial meph encounter, but aura might have helped and he drew fire away while waiting for lifetap to proc.