Removing the disclaimer as it is now tested in more modes - Slash, Arena, Joust, and Domination (though they just removed that in 11.5). I swap between building 1 or 2 tank items (like axe/cloak) and the rest damage, or just going full damage.
I added the "Alternate" build items, that you can swap one of or all 4 for the last 4 items in the build. This makes it more of a straight mage build, which I see many people doing with Charon these days, but I've also seen some very good tanky builds.
Still haven't played with him in Conquest (only just started playing it).
UPDATE NOTES FOR YEAR 11:
Not much changed - lost the recipes, and fewer options with consolidated relics, though there are a few new shards and non-relic items. The new items aren't right for this build, but it does benefit from the increase in lifesteal (now 30%-45% depending on health level, instead of 20%-30%). For those not aware, all the lifesteal is 50% more against gods, but then half for minions/jungle, which ends up being 25% less overall.
However, note that with Typhon's passive power boost based on lifesteal, the build gets an extra 15-22.5 power compared to Year 10, for free.
Also Note: I actually played against someone using this build the other day (that was a surprise!) - when I was on a different character. He killed me several times by catching me with dash or with the ultimate. Very annoying with this much damage, the dash up so much, and the ultimate wave travelling way too far...
MAIN BUILD NOTES:
Overall this build ends up somewhere between a more damaging Guardian and close to a pure Mage. It's been working good on low-end arena and a bit of Joust that I've played, but I'm a noob at this point. I tried a more tanky build and was barely making dents in any players, even mages - to the point they even started ignoring me. With this build they have to pay attention.
It's a good build for a positive kill ratio on winning games, and good shot at top assists.
The build focuses mainly on CDR (20-30% early, 40% full), Magic Power (over 500 at end with passives triggered), and Penetration (30% at full build) to give his abilities a bigger punch. This mainly at the cost of HP and protections. Auto-attack will be okay, but is not the focus. Charon's ultimate in particular can hit hard with full build at 20 across multiple players. A 30% lifesteal is also featured that can keep you topped off (up to 15% extra depending on health from Bancrofts, and with the 15% boost to heal amount on Typhon's it is effectively 34%-52%).
The lack of protections leaves him more vulnerable than more usual builds, though Charon still has decent health (ends up at 2846) and great mobility. The lifesteal really does help as well as he has a lot of AOE damage that can multiply it. I focus one of the relics (Wings) on mobility to enhance that, providing extra ability to either escape (slows or keep someone out of range), or to pursue a runner for the kill. This does mean he needs to 'bob and weave' a lot though, and get used to drive-bys in a scared-assassin sort of way, and play a little bit like a mage. He can do moderate damage and be a distraction right in the mix - momentarily - usually without getting killed. Hard Crowd Control is his bane here, so he need to learn positioning and erratic, assassin-like movement to avoid getting caught.
However, with this build Charon packs a punch - even his wave/dash ability hits a good amount, and can wipe out most or all of minions health while covering such a wide swath of the battle field he's can hit multiple enemy gods as well. Add in the wave's root for 0.5-1 s and this tips the battle when other teammates are around to take advantage - and helps him get away with his drive-bys. You can also chase people down with the wave, rooting and damaging them, then cancel the wave just past them, turn and throw another ability while they are still rooted - at minimum forcing them to spend relics or escape abilities, if they have them up. Quite fun when you can accomplish this and get away with it, and much better than catching up but doing minimal damage with a more tanky build.
Lifesteal is also a feature here, and really what keeps me from including Soul Reaver, Divine Ruin and other standard damage items, that I'd like to work into the build. It's one of those things that you don't really notice directly, but it probably saves you at least 2-3 trips back to base when things are going well - including trips from death, not just recalling. That means more XP, gold, and ability to push the enemy and support the team. Since Bancroft's provide both more power and lifesteal when health drops, and there is synergy with Typhon's boost to lifesteal heal amount and power, I don't suggest swapping Bancroft's out, and Typhon's is needed for the 20% penetration without significantly changing the build.
Note that lifesteal may be reduced by various anti-heal effects (such as tainted starter item line, Pestilence, Divine Ruin, etc.), but it's good to be aware and perhaps adjust some tactics at the margins.
