We saw the debut of Von Grissle (variant human noble UA ranger 1, lucky feat), who fancies himself a gentleman monster hunter, tonight in the fourth session of The Delve. Accompanying him was Bruenor Stoutbarrel (hill dwarf moon druid 2/barbarian 1), Lucien Bimblesnicket (forest gnome wizard 1), and Ungala (half-elf bard 1).
Natural Explorer was great. With the party ignoring the difficult terrain posed by the Duskwood, the travel time from the depressing village of Grimdark is cut in half with no chance of getting lost (which adds more time) and reduced the chance of a random encounter on the way to the dungeon. This also virtually guaranteed the party can get up to two short rests that expedition plus plenty of time to explore before the Thrice-Damned Horn sounds, heralding the return of the dungeon to The Shade.
Of course, the dice went against the party despite the reduced chance of encounter. The party came across a wide stream which the druid and bard wanted to cross with a large fallen tree they found. Natural Explorer came in handy again, with Von Grissle learning useful information on flying snakes that frequented the area based on the shed skin he found. It wasn't long before a flock of them appeared on the far side of the stream, opposite Von Grissle and Lucien. The dice went against them again and the snakes won initiative - a few seconds full of fangs later, Lucien and Von Grissle were dying, poisoned. The druid and bard dropped their log and rushed into a harrowing battle. The PCs put a lot of resources on the line to win this one, but Von Grissle did roll a 20 on his Death Save which was awesome because he was about to get back into things just in time to kill the last flying snake. (Nothing to do with UA ranger though.)
In the dungeon, Natural Explorer is useful again because there's quite a bit of rubble around the dungeon, difficult terrain Von Grissle can ignore. The rest of the party frequently had poorer mobility, especially when moving around the ballista they captured from the hobgoblins. (They used this ballista to bash down the spiked iron door to the Sepulcher of Hecubus the Damned, Oracle of Dis. But what they saw beyond discouraged any further exploration of it.)
Once the goblins, their hobgoblin leaders, newborns and gestation chambers were purged, Von Grissle wanted to hunt down the phase spider said to live on the third floor (a fact learned by Bruenor in an earlier expedition). Favored Enemy: Monstrosity came in handy here for the damage when the phase spider attacked their back rank as the party toyed with a gray ooze in an unfinished section of the catacombs on Level 3. It savaged the druid Bruenor before the party retaliated and drove it back into the Shade. A few tense moments later in which everyone readied for an attack from out of nowhere, the phase spider returned! Von Gissle's readied action - a quarrel from his trusty crossbow - finished it off before it could sink its fangs into anyone. The bonus damage (+2) was exactly enough to kill it.
At this point the party was fairly well drained, so after some examination of the Sarcophagus of Nuada the Famished and the immovable rod that holds shut its stone lid (on Level 1), they left the dungeon and decided to just head back to Grimdark rather than set up camp for a short rest. Natural Explorer was useful again here - reducing the odds of a random encounter which went their way this time.
So basically very useful inside the dungeon and out. The druid was naturally the one to take the brunt of incoming attacks and dish them back out. The ranger laid down good damage. The wizard and bard were mostly in support roles with some control effects that were useful.
