The Void Burrower. Despite seeing only nerfs to her kit since her release, Rek'Sai is still considered one of the most powerful junglers in League of Legends. First, let's discuss some integral parts of jungling.

As a jungler, there are a few things that you want to make sure you do.

1. Pressure lanes.
2. Ward to "counter" the enemy jungler.
3. Establish control around neutral objectives.
4. Countergank the enemy jungler.
5. Farm so you're not too far behind.
6. Provide disruption in teamfights, dive their back line, or peel for your carries (depending on your item build).

Now, let's discuss why Rek'Sai excels at each of these points.

1. Lane pressure.

Rek'Sai is a champion that has a powerful early game and can set up ganks pretty effectively. With her burrow (W), she can ensure that there's no one to countergank as getting into position. Then, with her tunnel (E), she can get behind and underneath the laner she's ganking. Afterwards, all Rek'Sai needs to do is Unburrow (W) to knock them up and then use her other abilities to dish out damage while her laner helps in the gank. She can also utilize her already established tunnels as bait. Most players have a tendency to try to collapse Rek'Sai tunnels and, if you set up around it with your team, you can collapse on whoever is trying to and kill them or force a summoner.

2. Ward to "counter" the enemy jungler.

As a jungler, one of your core jobs is to make sure you ward the enemy jungle and jungle entrances to help stop the enemy jungler from getting off successful ganks. Rek'Sai has great mobility with the use of her tunnels and it allows her to get into the enemy jungle for deep wards and quickly get out. In fact, warding is so effective on her that it's common practice to build Sightstone and provide consistent vision. This can effectively shut down more gank focused junglers.

3. Establish control around neutral objectives.

Due to Rek'Sai's ultimate which can function like a teleport, she can get across the map really easily. Because of this, a Rek'Sai can establish vision control around neutral objectives like Dragon and Baron and set up tunnels in obscure places. If the enemy team tries to start up an objective, you can get there instantly no matter where you are on the map as long as your ultimate is off cooldown. Rek'Sai also has true damage on her E (as long as you have 100% on your fury bar) so you can combo your E and smite to secure objectives.

4. Countergank the enemy jungler.

Similar to the point about neutral objectives, Rek'Sai can set up tunnels near all her lanes. This effectively allows you to countergank any lane as long as your ultimate is off cooldown and as long as you're paying attention. Since a successful countergank sets both the enemy laner and the enemy jungler behind, this is critical. It's fairly easy to pull off with map awareness and can snowball your team's lead very easily. Just like the previous point, you can be doing anything, anywhere on the map, and can be at a tunnel instantly.

5. Farm

For one, Rek'Sai has very quick clear. Rek'Sai's Queen's Wrath (Q) can quickly clear the small minions on camps and you can disrupt the camps by burrowing and unburrowing underneath them. Rek'Sai can also sustain effectively due to her passive which regenerates her health when she's burrowed as long as she has fury. Plus, as long as you have tunnels on the map, you can base and then use your ultimate to go back to one of your tunnels. This allows for quick and efficient farming.

6. Role in teamfights.

Depending on how fed a Rek'Sai is and what build she decides to go, Rek'Sai can do a variety of things in a teamfight. A fed Rek'Sai with more damage (e.g. Warrior enchantment + a damage item) can dive the backline and decimate the squishy targets. However, a more tank focused Rek'Sai (e.g. Cinderhulk + full tank) can focus more on disruption with her knockup as well as peeling for the carries so they can dish out more damage. That being said, she still does a large amount of damage and can still be very oppressive towards the enemy carries.

Along with all these points, Rek'Sai has found that she has adapted to tank meta fairly well. Most of the cinderhulk junglers aren't very powerful early game. Rek'Sai, however, is an incredibly powerful early/mid game champion. With the nerfs to her AD ratios on her Q, a lot of Rek'Sai players have adopted going towards a Cinderhulk, full tank route. This allows you to still be a force to be reckoned with in the early game but you can live for longer and provide great peel and disruption in teamfights later in the game.

While a lot of the more powerful picks right now include champions like Sejuani and Gragas, Rek'Sai has a place in the top tier junglers.